WINTER ISLAND - CONSERVATION COMMISSION (3) DOA - Winter Island Fort
'� Pickering Light _
310 CMR 10. 99 DEP File No.
(To be provided by DEP)
Form 2
City/Tan Salem
Applicant City of Salem
Coamonwealth 9/25/98
of Massachusetts Date Request Filed
Determination of Applicability
Massachusetts Wetlands Protection Act, G.L. c. 131, 540
From Salem Conservation Commission - Issuing Authority
To c/o Gary Moore, Winter Island Parkmitof a€ Sa'exR
(Name of Person making request) (Name property owner)
Cit of Salem 93 Washington Street Salem, MA 0197
Address y Address
This determination is issued and delivered as follows:
® by hand delivery to..,person making request on 1/19/99 (date)
❑' by certified mail, return receipt requested on (date)
Pursuant to the authority of G.L. c.131, §40., the Commission
has considered your request for a Determination of Applicability and its sup-
porting documentation, and has made the following determination (check whichever
is applicable) :
Location: street Address 50 Winter Island Road
Lot Number:
This Determination is positive.
1. ❑ The area described below, which includes all/part of the area described
in your request, is an Area Subject to Protection Under the Act.
Therefore, any removing, filing, dredging or altering of that area
requires the filing of a Notice of Intent.
2. ❑ The work described below, which includes all/partof the work described
in your request, is within an Area subject to Protection Under the Act and
will remove, fill, dredge or alter that area. Therefore, said work
requires the filing of a Notice of Intent.
2-1
Effective 11/10/89
3 . ❑ The work described below, which includes all/part of the work described
in your request, is within the Buffer Zone as defined in the regulations.
and will alter an Area subDect to Protection Under the Act. Therefore,
said work requires the filing of a Notice of Intent .
This Determination is negative:
1 . ❑ The area described in your request is not an Area Subject to Protection
Under the Act.
2. ❑ The work described in your request is within an Area Subject to Protectio:.
Under the Act, but will not remove, fill, dredge, or alter that arec..
Therefore, said work does not require the filing of a Notice of Intent.
3 . [] The work described in your request is within the Buffer Zone, as defined
in the regulations, but will not alter an Area Subject to Protection Under
the Act. Therefore, said work does not require the filing of a Notice of
Intent. All work shall be performed at 1/2 tide or less and shall be
encapsulated tod ture blastin .
4 . C3 The area describe in your request is Subject to Protection Under the Act,
but since the work described therein meets the requirements for the
following exemption, as specified in the Act and the regulations, no
Notice of Intent is required:
Issued by Sa Conservation Commission
*.atu )
/
This Determination must be signed by a majority of the Conservation Commission.
On this eight day of October 19 98 , before me
personally appeared the above mentioned to me known to be the
person described in, and who executed, the foregoing instrument, and
acknowledged that - �/ ' executed the same as his/her `free act and deed.
STEPHEN DIBBLE
NotaryPublic
My Commission Expires Nov.12,200=.
Not ry Public My Commission Expires
Th1s Determination does not relieve the applicant from complying with all other applicable federal, state or
.local statutes, ordinances, by-laws or regulations. This Determination shall be valid for three years from the
date of issuance.
The applicant, the owner, any person aggrieved by this Determination, any owner of land abutting the land upon
which the proposed work is to be done, or any ten residents of the city or town in which such land is located,
are hereby notified of their right to recuest the Department of Environmental Protection to issue a Superseding
Determination of Applicability, providing the request is made by certified mail or hand delivery to the
Department, with the appropriate filing fee and Fee Transmittal Form as provided in 310 CMR 10.03(7) within ten
days from the date of issuance of this Determination. A copy of the request shall at the same time be sent by
certified mail or hand delivery to the Conservation Commission and the applicant. t
i
2-2A f
a/3 98
•.,��u" coy,
y
Conservation Commissim
Salem. Massachusetts 01970
� tiW
"IA tis
City of Salem
Conservation Commission
Will hold a public hearing for a Determination of Applicability under the Wetlands Protection
Act, Massachusetts General Laws, Chapter 131, Section 40, at the request of the City of Salem.
The purpose of the hearing is to discuss the proposed renovation to Fort Pickering Light, Winter
Island Park. This hearing will be held on Thursday, October 8, 1998 at 7:00 p.m. in the second
floor conference room at One Salem Green.
Mark George
Chairman
October 1, 1998
Please send bill to:
City of Salem
Attn: Jane Guy
Community Development
One Salem Green
Salem. MA 01970
310 CMR 10. 99 Dap pile No.
(1b be provided by DEP)
Form 1
City/To
Applicant
Co®onreal th
of Massachusetts
Request for a Determination of Applicability
Massachusetts Wetlands Protection Act, G.L. c. 131, §40
1. I, the undersigned, hereby request that the Q .I W\ .
Conservation Commission make a determination as to whether the area,
described below, or work to be performed on said area, also described below,
is subject to the jurisdiction of the wetlands Protection Act, G.L. c. 131,
§40.
2. The area is described as follows. (Use mans or plans, if necessary, to
provide a description and the location of the/ area subject to this request. )
Location: Street Address
Lot Number:
3. The work in said area is described below. (Use additional paper, if
necessary, to describe the proposed work. )
1-1
Effective 11/10/89
4 . The owner(s) of the area, if not the person makingthisrequest, has been
given written notification of this request on (date)
The name (s) and address (es) of the owner(s) :
Sa l'e v�
S. I have filed a complete copy of this request with the appropriate regional
office of the Massachusetts Department of Environmental Protection
(date)
DEP Northeast Regional Office DEP Southeast Regional Office
10 Commerce Way 20 Riverside Drive
Woburn, MA 01801 Route 105
Lakeville, MA 02347
DEP Central Regional Office DEP Western Regional Office.
75 Grove Street State House West, 4th Floor
Worcester, MA 01605 436 Dwight Street
.Springfield, hIA 01103
6 . I understand that notification of this request will be placed in a local
newspaper at my expense in accordance with Section 10.5 (3) (b) 1 of the !,
regulations by the Conservation Commission and that I will be billed
accordingly.
Signature n n Name C9A//Z /YV Vl�f�g Q'
Address I/, 5�. Pr Tel. `( 7rl L3
LP Ar;
1-2
CITY OF SALEM,MASSACHUSETTS
Zvi k &ReCreation D
e
partm
en,Winter Island
50 Winter Island Road
Salem,Massachusetts 01970
Gary Moore (508)745-9430 E.Lawrence McIntire
Manager Fax:740-9299 Superintendent
September 23. 199E
Jane Guv Ft . Pickering Licht
Salem Planning Department
Gary M. Moore . Manager
Winter Island Park.
** MAINTENANCE SPECIFICATIONS. FORT PICKERING LIGHT ***
Following below are the repair and maintenance specifications for
the complete refurbishment of Fort Pickering Llghthouse at Winter
Island Park . Reference to the " Historic Lighthouse Preservation
Handbook" should be made by all prospective contractors to more fully
understand requirements and methods called for in this restoration
effort .
Description of Light : Fort Pickering Light was first constructed in
1871 by the National Lighthouse Service . Her lense height is some 28'
above mean high water . Rer concrete base sits on a ledge that places
the Lighthouse in total water surroundlncs at half tide of better .
Other important dimensions are as follows (close approximations) :
- concrete base* = 10' heiaht
41 ' circumference
- conical cast iron plate base tower = 18' height
appprox 630 sq. ft . surface . area 35' circumference
- lantern tower (polygonal )= 9' heiaht
32' circumference
panteisenneethk /4thki36/ circumference
- lantern iron plate
1/41' thick 27"x1/2" gzgs
- lantern roof is cast iron to ball vent top and lightning rod
WORK TO BE PERFORMED:
Iron work repairs:
- welding of three (3) parapet braces to re-attach to conical tower
- refurbish lantern bars to best accept installation of new glazings
(ea. ) metal polymers that can be molded or shaped to match existing
contours.
- refurbish access door hinges (3' x 7' cast iron door)
- remove exterior electrical conduit at base of tower
Painting:
- complete removal of rust from all iron surfaces using low pressure
aggregate blast method (ref . " . .Preservation Handbook" )
- preparation of all white and black painted surfaces to accept primer
- filling of all seams with butyl rubber or poly sulfide calking
- painting of all exposed Iron surfaces with appropriate primer
- painting of all black and white surfaces with second coat of primer
- finish painting of all exposed surfaces with appropriate premium
paint (two coats) , gloss white and flat black typical
Lantern glass replacement :
— replace present glazings with tempered laminated glass. sized for
code required wind load and appropriately fitted with casket
material that will prevent breakage under tower racking conditions
(ref .Part IV .G.paae 17 of Handbook)
( not part of this refurbishment effort )
.,'_ rH�storic Lighthouse Preservation:
ONx
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Figure I. Cast-iron-and-steel skeletal 191-foot-tall tower at
Capc Charles, Virginia
Second to masonry, iron was the most Iron was also used for the production of
common lighthouse construction material. architectural trim features such as gallery
For lighthouse construction, iron was used deck brackets, entryway pilasters and
in a variety of its commercially pediments, doors, and prefabricated lantern
manufactured alloys: wrought iron, cast components. These iron features were used
iron, steel, galvanized iron and steel, and on masonry and wood as well as iron
stainless steel. In historic lighthouses the lighthouses. Other iron alloys such as steel,
most widely used alloy was cast iron. The galvanized iron and steel, and stainless steel
use of cast iron in lighthouse construction are mostly found in modern additions such
ranged from simple prefabricated lanterns as handrails, equipment brackets, security
to caisson-style foundations to 190-foot-tall doors, etc.
first-order coastal towers. For more on the This section will discuss the preservation of
variety of iron lighthouse construction types iron alloys used in lighthouse tower
refer to Part II., History of the Lighthouse construction and decoration. Because of
Service and Lighthouse Construction their similar properties, the various iron
Types. alloys will be discussed together; special
treatments concerning a specific alloy will
Historic Lighthouse Preservation Handbook Part IV. B, Page 1
O
z:i 6 L+Y t
Figure 2. Example of a keeper's quarters fitted with a
prefabricated cast-iron-and-steel lantern.
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Figure 4. Double-«all past-iron Inst-order 163-foot-tall
-- --� 3 coastal tower at Cape liens. Vin,inia
Figure 3 Example ample of n Al-cast-iron construction
"spark Plue"caisson-style lighthouse.
be discussed accordingly. The use of iron different manners. Second, cast iron can be
in the construction of lanterns and the cast into virtually any shape that is required
special considerations associated with iron for structural or decorative purposes. To
in the presence of unlike metal corrosion form complex shapes and structural
(galvanic corrosion) will be discussed in the systems, these castings were designed with
Lantern section. Other metals such as brass flanges that made it possible to bolt the
and bronze will also be discussed in the component parts together. This
Lantern section. prefabricated style of construction
facilitated the erection of lighthouses in a
Iron Alloys Found in Historic timely, economical manner. This method
Lighthouses also allowed for the dismantling and
relocation of a lighthouse if site conditions
Of the iron alloys, cast iron was a perfect were compromised by encroaching erosion.
choice for lighthouse construction for two The various steel alloys were used
principal reasons. First, cast iron is throughout the structure of a historic
relatively resistant to corrosion because of lighthouse, but to a lesser degree than cast
its microstructure component compounds—
graphite and phosphide eutectic. These iron. Most mild steel, stainless steel, and
compounds are not present in steel, which galvanized steel components have been
explains why the two materials corrode in used in modern additions or repairs. These
components appear mostly as pre-
Part IV. B, Page 2 IRON
§ {4
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nn.
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Figure 5. A view of decorative-rope nautical-style cast-
iron window surrounds on Cape Canaveral Lighthouse. ,
manufactured items such as structural 'I'
I'
beams, replacement handrails, equipment
brackets, and items that can be fabricated J
into functional parts of the lighthouse.
t ,
a
t
Figure 6. A view of the inner cavity and skeletal structure n
of the Cape Henry Lighthouse.
lL
3
Iron Alloys Commonly Found in
Historic Lighthouses
Sedioro .F G""y':ur'U i(irh.,• ,a
Wrought iron is relatively soft,malleable,
l ".:-. _Q_ 'o _ — ` I tough, fatigue-resistant, and easily
y,l. -F, a^ worked by forging, bending,rolling,and
drawing. Until steel was available,
wrought iron was used structurally for
beams and girders as it had strength in
both tension and compression. During
F±.La. I i the late 19th and early 20th centuries, it
was not unusual to find a mixture of cast-
�l 1
o
<io iron columns and wrought iron or steel
\\'v4 �* ,I fe` p : Ir '• ,, beams in the same lighthouse. Currently,
Via.`z.., \a •. 1__ very little wrought iron is being produced.
\� ,.• •, , ,i `'•y
Cast iron is an iron-carbon alloy with a
t;_"•`. F �, high carbon content. It is easily poured
A �St while molten into molds,making possible
7'r` .W�rtia I rY�� numerous decorative and structural uses.
Sj41ir:Ztrr.r Cast iron is too hard and brittle,however,
to be shaped by hammering,rolling,or
pressing. Cast iron contains in its
"
microstructure several relatively
- • "' - -- '6 corrosion resistant components which are
Z mostly absent from the microstructure of
Figure 7. Shop drawings used for the production of cast-iron steel. Because of this,the two materials
lighthouse parts for a screwpile lighthouse.
corrode in different manners. It is more
rigid(highly resistant to buckling)than
other forms of iron and can withstand
Historic Lighthouse Preservation Handbook Part IV. B, Page 3
great compressive loads, which helps account for its
ubiquitous use for lighthouse tower structure
components such as wall plates,columns, sockets,
struts,deck plates,etc. Cast iron does have some
drawbacks. There is the potential for inherent flaws in
cast pieces such as trapped air pockets or foreign
material such as casting sand or slag trapped in the iron
during the casting process. These flaws can be avoided
if the castings are thoroughly inspected and the casting
process is performed to accepted industry tolerances.
Steel is an alloy of iron and carbon that contains not
more than 2%carbon, and is malleable in block or
ingot form. Steel may include phosphorus, sulfur,
oxygen, manganese, silicon, aluminum, copper,
titanium, molybendum, and nickel. The properties of
steel can vary greatly in relation to the chemical
composition and the type of heat treatment and
mechanical working used during manufacture.
a Characteristics affected by these differences include
-l_" s , a strength, hardness, ductility, resistance to abrasion,
n weldability, machinability, and resistance to corrosion.
A grade of medium carbon steel is used for most
Figure 8. An example of the level of detail lighthouse applications today such as handrails,
.¢hicccd,cith cast-iron construction. equipment brackets, new light support structures, etc.
_ Galvanized steel and iron consist of steel or iron with a
v
zinc coating, which makes it high- resistant to
g, � Y
corrosion. As.in the past, zinc is still widely used as a
protective coating for iron and steel. A major
-
-�-._-; _>:.;r advantage of zinc coating on iron is that if the zinc is
s worn away or broken and the iron is exposed to the
atmosphere, galvanic corrosion of the more base zinc
tn. Er. o occurs, protecting the more noble iron. (The terns
t base and noble refer to the relative reactivity of the zinc
a and iron. A metal that is considered a base is more
Ie ��.�•
reactive than a metal that is considered noble. These
�r properties are directly related to the number of free
' i_ure 9. A modern range tinder ached to the electrons that exist in the molecular structure of the
ealkry deck using modern steel members. metal.)
Stainless steel is defined as a steel containing sufficient
chromium, or chromium and nickel, to render it highly
resistant to corrosion. Stainless steel is malleable,
hardened by cold working, and resistant to oxidation,
corrosion, and heat. It has characteristics of high
thermal expansion and low heat conductivity, and can
a be forged, soldered, brazed, and welded. Because of its
e relatively inert properties, stainless steel components
t are mostly found in replacement parts such as bolts
where the possibility of galvanic corrosion could occur.
3
Stainless steel is available in various grades. Given the
complexity of the issues and potential application, the
Figure 10. Close-up of a lantern glass frame:note selection of the proper grade of stainless steel for use in
the usa of stainless steel bolts;the lower clamps are amarine environment requires careful evaluation by an
:also stainless steel that have been painted black.
engineer.
Part V. B, Page 4 IRON
Causes of Iron Deterioration and
Failure
Iron lighthouse components are subjected to
t> a host of forces associated with a marine
environment. How successfully a lighthouse
resists these pressures depends on how well
it is designed and maintained. Iron
lighthouses that are poorly maintained will
deteriorate rapidly.
In scientific terms,deterioration is generally
s� defined as a decrease in the ability of the
{ ' material to fulfill the function for which it
was intended. It usually refers to the
breakdown of a material because of natural
`^ causes, although deterioration can also be
. v o either directly or indirectly caused by man.
Deterioration can also be defined as the
j changing of a material from a higher to a
t o lower energy state. Although deterioration
usually implies a chemical change, under
" k some conditions the change can be physical.
- There are five possible forces that can act on
Figure 11. Detail view of a steel ladder that has been an iron lighthouse component and cause its
uniformly attacked by corrosion.
failure: corrosion, inherent flaws,
mechanical breakdown, weathering, and
connection failure.
Corrosion
Corrosion, in one form or another, is the major cause of the deterioration of iron lighthouse
components. Often called oxidation, it is the chemical reaction of a metal with oxygen or
other substances. The deterioration of iron lighthouse components is a complex process
because the type and degree of corrosion is affected by minor variations in environment,
contact with other metals and materials, and the composition of the component itself.
Upon exposure to the atmosphere, almost all new or newly cleaned metals become coated
with a thin film of metallic oxide, which is a result of the reaction of the metal with oxygen.
This film may modify the properties of the metal and make it less susceptible to further
corrosion. In the case of rusting iron, however, the oxide does not form a protective coating
but rather promotes the continued corrosion of the metal. The three most common types of
corrosion experienced by iron lighthouse components are as follows:
• Oxidation or rusting occurs rapidly when the iron component is exposed to moisture and air. The
minimum relative humidity necessary to promote rusting is 65%, but this figure can be lower in the
presence of corrosive agents,such as sea water,salt air, acids, acid precipitation, soils,and some
sulfur compounds present in the atmosphere, which act as catalysts in the oxidation process.
Rusting is accelerated in situations where the shape of the iron details provide pockets or crevices
to trap and hold liquid corrosive agents. Furthermore, once a rust film forms, its porous surface
acts as a reservoir for liquids, which in turn causes further corrosion. If this process is not arrested,
it will continue until the iron is entirely consumed by corrosion, leaving nothing but rust.
Galvanic corrosion is an electrochemical action that results when two dissimilar metals react
together in the presence of an electrolyte, such as water containing salts or hydrogen ions. The
Historic lighthouse Preservation Handbook Part IV. B, Page 5
severity of the galvanic corrosion depends
on the difference in potential between the
two metals,their relative surface areas,
i,z,z t c � and span of time. If the more noble metal
Y (higher position in electrochemical series)
is much larger in area than the baser, or
c I, illi I less noble, metal,the deterioration of the
$ I�, baser metal will be more rapid and severe.
g If the more noble metal is much smaller in
;. a area than the baser metal,the deterioration
of the baser metal will be much less
v'A
3 significant. Iron lighthouse components
Figure 12. Close-up of localized corrosion or pitting will be attacked and corroded when they
where the corrosion has eaten through the cast iron. are adjacent to more noble metals such as
lead or copper. For more on galvanic
corrosion refer to the Lantern.
Graphitization of cast iron, a less common
problem, occurs in the presence of acid
precipitation or seawater. As the iron
corrodes, the porous graphite(soft carbon)
corrosion residue is impregnated with
insoluble corrosion products. As a result,
the cast-iron element retains its appearance
and shape but is weaker structurally.
Graphitization occurs where cast iron is
left unpainted for long periods or where
caulked joints have failed and acidic
rainwater has corroded pieces from the
backside. Testing and identification of
graphitization is accomplished by scraping
through the surface with a knife to reveal
the crumbling of the iron beneath. Where
extensive graphitization occurs, usually
I the only solution is replacement of the
�r
damaged element.
x�v I
C Inherent Flaws
g t rl, •� ri� -6`,i IFI o
z s'• m a Castings may also be fractured or flawed as a
result of imperfections in the original
manufacturing process, such as air holes,
Figure 13. View of a steel railing where corrosion has cracks, and cinders. or cold shuts (caused by
occurred in distinct locations either because of the"freezing"of the surface of the molten
o;irwtions in composition or localized failure of the
coming s.stcni. iron during casting because of improper or
interrupted pouring). Brittleness is another
problem occasionally found in old cast-iron
elements. It may be a result of excessive phosphorus in the iron, or chilling during the
casting process.
The corrosion of iron lighthouse components takes several forms:
• Uniform attack is where the iron component corrodes evenly where exposed to corrosive agents.
Putin- is the localized corrosive attack on the iron component.
Selective Attack can occur where an iron component's composition is not homogeneous and certain
areas are attacked more than others.
Part IV. B, Page 6 IRON
Stress corrosion cracking can occur where ,
stresses were induced into the iron component
in the pulling or bending process of fi
metalworking and the component later t
subjected to a corrosive environment. For u K
F 2F' Y x tW
example,stainless steels can crack in
environments containing chloride, and carbon
steels in nitrate,cyanide, or strong caustic
solutions. °
• Erosion occurs when the corrosion-resistant `f
film or oxide or layer of protective corrosion W k
product is removed by abrasion,exposing fresh 3
metal to the corrosive agents. Figure 15. As corrosion attacked this steel handrail,
wind and airborne sand eroded the loose and flaking
Mechanical Breakdown surface rust.
Iron lighthouse components can also fail :
from purely physical causes such as abrasion, �a
or a combination of physical and chemical
attack, such as weathering and stress
corrosion cracking.
Abrasion is the erosion of the iron components
caused by moving dirt,dust,sand,grit, sleet, _
and hail, or rubbing by another lighthouse
component or human element. Abrasives can
fir _ �Y�•,Tks Y� .y._. .�� ^ '...''
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Figure 16. As corrosion attacked this steel turnbuckle,
wind and airborne sand eroded away the flaking rust.
H
also encourage corrosion by removing the
protective coating(paint)from the iron
1 lighthouse component.
n
0 Fatigue is failure of an iron component by the
3 repeated application of cyclic stresses below
Figure 14. Nearly 30%of this ventilation shroud has the elastic limit—the greatest stress a material
been lost to two forms of abrasion:first,sand or grit can withstand without permanent deformation
blasting abraded away a majority of the material; after removal of the load. It results from a
second,human touch has smoothed the once rough gradual or progressive fracture of the crystals.
surface.
Historic Lighthouse Preservation Handbook Part IV. B, Page 7
Overloading is the stressing of an iron
lighthouse component beyond its yield point ° I T ;•
so that permanent deformation, fracturing, or
failure occurs. it can fait through the
application of static loads,dynamic loads,
thermal stresses, and settlement stresses
either singly or in combination. "Buckling"
is a form of permanent deformation from
overloading which is usually caused by
excessive weight but can also be caused by y ` '''" o
thermal stresses. Members can also be =_
overloaded if their support is removed and - _ rL
loads are redistributed to other members 3
which can become overstressed and Figure 17. The cyclic pressure of the different rates
deformed. An iron lighthouse component of expansion and contraction of the exterior cast-iron
can fail or become permanently deformed by plates and the interior brick linins of the caisson-style
the phenomenon known as rust-jacking. The liehthouse has caused the cast-iron plates to fatigue
and crack.
failure or deformation is the result of the
er x
expansion of the iron component as it :t�
oxidizes. This expansion"jacks"the two
members apart.
Weathering
An iron liehthouse component subjected to 't
the weather is exposed to various chemical '
and physical agents singly and in �,
combinations of several at one time. The t
result is a kind of synergism where the total _ o
effect is greater than the sum of the —.` k
3
individual effects taken separately. For Figure 18. The internal structural skeleton of this
example, the rate of corrosion accelerates lighthouse is cracked because of oecrloading possibly
withincreases oftemperature, humidity, during assembly.
and surface deposits of salts, dirt, and
pollution. a .-
Connection Failure , h
�_The failure of the connections of iron ` y
lighthouse components,especially ..` -r
structural members, can also be caused by '
a combination of physical and/or chemical
o
agents. The most common type of
connections used for iron structural
elements of historic lighthouses include �
bolting, riveting, pinning, and welding.
These connections can fall through the Figure 19. This handrail has bcendama_cd by rust-
jacking;rusting began between the two pieces of flat
overloading, fatiguing,or corrosion of tlhe bar stock that formed the rail.
connectors. Common examples of this
t\pe of failure include the corrosion, usually by concentration cells(or battery affect caused
by dissimilar metals), of bolt heads, rivets, and areas covered by fastening plates. The
effective cross-sectional area of the connectors is often reduced by corrosion, making the
connectors more susceptible to stress failure.
Part IV. B, Page 8 IRON
Inspecting for Possible Problems
In order to develop an effective treatment plan for iron lighthouse problems, an in-depth
inspection must be made of the iron lighthouse and its immediate surroundings. The
following chart is a listing of locations that should be inspected regularly. Associated with
these locations are the possible problems to look for during the inspection.
Inspection Chart for Iron Lighthouses
THE SITE
Look For: Possible Problems:
Environment
General climatic conditions, including average Severe conditions can lead to deterioration of the
temperatures, wind speeds and directions, masonry foundation, which in turn could lead to
humidity levels, and average snow accumulation differential settlement that could ultimately damage
the iron lighthouse structure.
Number of freeze-thaw cycles Severe cycles can cause damage to iron lighthouse
components from frost action.
Location near sea Salt (chloride) in the air can lead to accelerated
corrosion of exposed iron surfaces.
Acid rain in the region or from nearby industry Acid rain can lead to accelerated corrosion of
exposed iron lighthouse components.
Proximity to a major road highway or railroad Vibrations are harmful to masonry foundation
mortar joints as well as iron lighthouse parts.
Repetitive vibration can cause premature failure in
iron components if the oscillation cycles fatigue
the metal to the point of failure.
Location in the Flood plain of a river, lake, or sea Floodwaters can bring damaging moisture to
foundations and walls; such damage can result in
differential settlement that could ultimately damage
the iron lighthouse structure.
Exposed or sheltered sections of a lighthouse Exposure to the sun and elements affects moisture
evaporation and rain penetration into the joints
between iron members. Sheltered areas such as
the underside of an iron gallery deck are highly
susceptible to corrosion and rust pitting because of
a tendency to accumulate moisture and the slow
drying rate without direct sunlight.
Historic Lighthouse Preservation Handbook Part IV. B, Page 9
Look For: Possible Problems:
Terrain
Soil type—clay, sand, rock The type of soil influences water drainage around
the structure. Excessive water in the soil could
lead to differential settlement that could ultimately
damage the iron structure. This is a minimal
concern for most iron lighthouses. Most iron
lighthouses were constructed on sites that had
been chosen for their soil and/or underlying strata
stability.
Slope away from lighthouse on all sides If no slope exists, puddles will form at the base of
the lighthouse walls during heavy rains, causing
water penetration and possible damage to
foundation systems that could lead to differential
settlement and ultimately to damage of the iron
structure.
Earth covering part of a brick or stone wall or ti1oisture accumulation or penetration is possible
foundation and could lead to differential settlement and
ultimately to damage of the iron structure.
Concrete or other impervious paving touching Water accumulation and rain back-splash onto the
walls walls which could lead to accelerated corrosion of
the iron wall structure.
Trees and Vegetation
Species of trees within 50 feet Elms and some poplars dry up clay soil, leading to
foundation failure and differential settlement that
could ultimately damage the iron lighthouse
structure.
Branches rubbing against a wall Branches abrade surfaces, possibly exposing bare
iron surfaces to the elements and accelerating
corrosion of the iron lighthouse structure.
Ivy or creepers on walls Leaves prevent proper drying of the painted iron
surface resulting in possible accelerated corrosion
of the iron surface. Tendrils from some species
can penetrate joints and can literally break the iron
lighthouse members.
THE LIGHTHOUSE
Overall Condition
General state of maintenance and repair A well maintained lighthouse should require fewer
major repairs.
Evidence of previous fire or flooding Such damage may have weakened the lighthouse
structural members or caused the introduction of
excessive moisture.
Part IV. B, Page 10 IRON
Look For: Possible Problems:
Signs of settlement Uneven settlement can crack foundations and lead
to differential settlement that could ultimately
damage the iron lighthouse.
Lantern
General condition A well maintained lantern should require fewer
major repairs. A leaking lantern may leave stains
under the gallery deck on the exterior of the
lighthouse as well as streaks on the interior walls
of the tower spaces below. This condition can
introduce excessive moisture into the interior of
the lighthouse and possibly cause accelerated
deterioration of interior features and structure.
Roof drains (usually associated with larger first- Clogged roof drains can hold water in the built-in
order lights) and covering guttering system and accelerate deterioration of the
roof covering. Small holes in the roof covering
can be moisture infiltration points.
Gallery decks, copings, and structural seams Gaps in gallery decking can allow water to
penetrate in the interior cavities of an iron tower
wal I.
Condition of storm panels Cracks and holes in storm panel glazing can
provide an infiltration point for moisture into the
lantern.
Humidity level within the lantern Non-functioning lantern vents can inhibit the
release of humid air from within the tower. The
water vapor will ultimately condense on the
surfaces inside the tower and lantern and possibly
cause accelerated corrosion of iron lantern
components.
Windows and Doors
Straight and square openings Deformed openings in the lighthouse structure may
be a sign of structure settlement.
Door and window sills sloped to shed water; drips If any of these is inadequate, water can penetrate
under sills to prevent water from running back into the wall and start corrosion from the inside
underneath; caulking out.
Foundation
Composition of foundation walls Stone or brick is more likely than concrete to
allow water to infiltrate.
Water condensation or other signs of moisture Wood joists or iron structural members resting on
masonry foundation walls may begin to rot or
corrode at the ends. Termites or algae, mold,
mildew, or moss may be present, causing damage
to the wood or masonry.
Historic Lighthouse Preservation Handbook Part IV. B, Page 11
Look For: Possible Problems:
Damp proof course This can impede rising damp, lessening
deterioration of the masonry wall.
Interior
Look for: Possible Problems:
Damp walls, stains on walls, rotting wood These indicate water infiltration.
Walls
Construction method—iron plate, sheet iron double Knowing how a tower wall is constructed will help
wall, iron plate with masonry infill, wood frame in analyzing problems and selecting appropriate
interior walls, etc. treatments.
�%lasonry-lined iron lighthouses Rust-jacking of iron members captured by masonry
infill may cause cracking of the infill. If the
masonry infill becomes wet, the different rates of
expansion and contraction of the masonry infill
and the iron sheathing during a freeze-thaw cycle
can cause the iron and masonry both to crack.
Sheet iron cavity walls Water infiltration will show as rust forms on the
interior of the cavity and appears as blistering on
the exterior of the panels. Rust streaks known as
'rust weep' or 'rust bleed' appearing on interior
wall surface plate seams may indicate water
infiltration has occurred.
Iron Components
Materials
Look for: Possible Problems:
Type of iron—wrought, cast, steel, galvanized Types of materials indicate the susceptibility or
steel, or stainless steel resistance to damage and proper repair method.
Areas of intricate castings or moldings These sections may need special attention or
protection during treatment.
Missing or broken iron components Missing material may allow water penetration.
Evidence of sandblasting, such as a pitted surface; Surface deterioration is not only aesthetically
evidence of erosion, flaking, scaling, or other form displeasing but can lead ultimately to the complete
of corrosion. deterioration of the lighthouse.
Dirt or stains Surface stains usually cause few problems other
than being unpleasant to look at. Accumulated
dirt or debris in built-in gutters or other 'pockets',
however, may trap water and cause accelerated
corrosion.
Part IV. 6, Page 12 IRON
Look for: Possible Problems:
Moisture
Water penetration through joints between iron Moisture can lead to deterioration of the iron and
components and between iron and other other parts of the lighthouse structure through
lighthouse components corrosion and rot. Water that has entered a cavity
may go unnoticed until extensive corrosion has
occurred.
Location and type of corrosion on surface The type of corrosion may indicate the source of
the deterioration; refer to the following section on
corrosion for more information.
Rust streaking or 'rust weep' present on interior or This condition indicates that moisture has
exterior wall surfaces near seams or construction penetrated the joint or interior cavity of the iron
joints in the iron structure wall. The water entry point should be identified
and sealed or the damaged area repaired.
Coatings
Paint; type of paint Various paint types require different treatment
methods and safety precautions, i.e., lead-based
paint hazards, etc.
Blistering, flaking, and peeling paint These conditions indicate the paint is at or near
the end of its effective life span.
Rust streaks or rust weep This indicates localized failure of the coating
system which has caused the exposed iron to
begin to rust. The rust scale should be removed
and the area spot painted in the interim until the
next repainting of the lighthouse.
Construction Joints
joints between iron lighthouse components were The white lead/linseed oil mixture hardens and
typically sealed with white lead mixed with becomes brittle over time and eventually falls out,
linseed oil thus allowing open joints for water infiltration.
Concrete or mortar used as a seam or cavity filler The concrete and mortar are very hard and can
easily break and thus allow for water infiltration;
cavities in an iron lighthouse that have been filled
with concrete or mortar are susceptible to
corrosion because of the alkalis present in the
concrete and mortar and the possible trapping of
water between the filler and the iron.
Iron copings over masonry portions of the The alkali nature of the mortar used in the
lighthouse such as watertables and window and masonry may cause the iron to prematurely rust.
door surrounds. These areas are prone to rust weep and should be
thoroughly cleaned of rust scale and painted
during the scheduled lighthouse repainting.
Historic Lighthouse Preservation Handbook Part IV. B, Page 13
PRESERVATION TREATMENTS
WARNING: Many of the maintenance and repair techniques described in this text, particularly those
relating to cleaning and painting, are potentially dangerous and should be carried out only by
experienced and qualified workmen using protective equipment suitable to the task. It may be
necessary to involve a USCG engineer or architect, preservation architect, or building conservator
familiar with lighthouse preservation to assess the condition of the iron and prepare contract
documents for its treatment.
Cast-iron and steel features such as gallery deck brackets, handrails, skeletal structures,
pilasters and door pediments, window architraves, as well as textured, finished surfaces
such as raised diamond pattern non-skid surfaces, are important in defining the historic
character of the lighthouse (see Figures 20 and 21). Itis essential that the character-
defining features are retained during any treatment. It should also be noted that while cast
iron is among the most durable of historic building materials, it is also the most susceptible
to damage by improper maintenance or repair techniques and by harsh or abrasive
cleaning methods. Therefore, all treatment should be executed using the gentlest means
possible. In Part V., Beyond Basic Preservation, examples of treatments that are
considered rehabilitation and restoration are illustrated and discussed.
OT
FF L.t
Sy Y f 4
K +no
oY,5I I4
y ,Ips
Figure 20. Figure 21.
Part V. B, Page 14 IRON
Protection and Stabilization (Mothballing)
Despite their inherent durability, a historic iron lighthouse that receives only minimal or
no routine maintenance is highly vulnerable to decay if it is not protected and stabilized
properly. To properly protect and stabilize a historic iron lighthouse, a thorough
inspection and diagnosis of all iron features: caisson structures, cast-iron plate walls,
decorative featured (cornices, door and window surrounds, decks, etc.) should be
performed using the inspection chart in the preceding section as a guide. The results of the
inspection are then used to develop a protection and stabilization plan. The following
recommended protection and stabilization guidelines for vacant historic iron lighthouses
are the minimum treatment requirements to prevent any further damage from occurring.
G 3 '
Weatherization
4 ts{
It is essential that all iron components be
completely weathertight. Water intrusion # +i
can be extremely detrimental to iron
components. If water enters the interior
cavity of an iron component it will cause s
corrosion to occur, or accumulated water
can freeze and the resulting expansion can 3
possibly crack the component.
Figure 22. Interior of a sheet-iron parapet wall that
To prevent moisture penetration be sure the is rusting from the inside to out along the lantern
following infiltration points are weathertight room door. This is the result of water entering the
interior cavity or the parapet wall.
or functioning properly:
• Lantern system:Cast-plate or sheet-iron lantern
parapet walls, all lantern glass, cast-iron frames,
and roofs must be weathertight. Caulk patches
should be used only as a temporary fix and not e:
relied on as a long-term treatment as they have a
mired functional life span. Refer to the -x
Lantern section of this handbook for more o
information concerning the weatherproofing of
the lantern components.
• Built-in guttering systems: In order to prevent
water from entering the interior cavity of �
double-wall iron or brick-lined iron wall << '
systems, all rain water guttering systems (lantern
roofs, or other tower roof forms) should be
cleaned and checked for holes. It is imperative
that all holes and non-functioning gutter system
components are repaired. For more information o
refer to the discussion on roofing in the Lantern y t
section of the handbook.
• Gallery decks:The seams between cast-iron
gallery deck plates must be made weathertight. _..
Figures th and 24. "Tutt types of gutters found on
If rust is already present, this must be removed
iron lighthouses;the gutters must be in proper
and the affected areas primed and painted. The working order and checked regularly during the
joints should be sealed with a high quality mothballing period.
Historic Lighthouse Preservation Handbook Part IV. B, Page 15
g
,1
' n n
Figure 25. The seams between the deck and wall plates of Figure 26. This steel casement window frame was not
this lighthouse were not properly sealed;as a result the sealed properly and as a result has begun rusting from the
areas collected water and began to rust. inside out.
sealant. The decking should be sloped away Ultimately, as part of a mothballing treatment,
from the lighthouse to shed the water away the entire lighthouse should have all loose paint
from the structure. If the decking material is not and corrosion removed and a new coating
weathertight, moisture can enter the interior applied to the entire surface according to the
cavity of the tower wall and cause damage that manufacturer's specifications. This action will
may go undetected until severe deterioration result in a coating system that will require
has occurred. See the Windows section of this minimal service during the mothballed period.
handbook for the proper caulk for this For more information refer to the paint and
application. Refer to the Lantern section of this coating systems discussion under the repair
handbook for more information concerning the treatment later in this section.
weatherproofing of gallery decks.
• Wall plates: The joints between cast-iron wall
plates must be kept weathertight. If rust is
already present, this must be removed and the t
affected areas primed and painted. The joints
should be sealed with a high-quality sealant. If
the wall plates are not weathertight, moisture ;
a
can enter the interior cavity of the tower wall =ar a
and cause damage that may go undetected. K
• Door and window frames and trim:The joints r
along the perimeter of iron door and window
trim and frames where the trim or frame is
attached to a masonry or iron tower must be
made weathertight. Open joints should be �-
cleaned of rust and loose paint. The affected
areas must be primed and painted, then sealed ;.
with a high-quality caulking. This will prevent
water from entering the interior cavity of either �lp t,j
the iron trim or the wall itself. See the
Windows section of this handbook for the —;
proper caulk for this application.
• Protective coatings:As a protective measure
and for recognition as a daymark, lighthouses 'a a a
were historically painted. As part of a r � 0
mothballing treatment, the exterior coating 3
should be checked for loose and flaking paint. , .
Any deteriorating areas should be scraped and removed Figured a Blistering paint,a as pictured here,should be .
and the affected areas properly primed and
spot-painted to match the existing color. painted.
Part IV. B, Page 16 IRON
Stabilization Ventilation
When mothballing an iron lighthouse or a Iron lighthouse towers are typically one of
lighthouse with iron components, all four possible construction types: single-wall
possible structural repairs should be made cast-iron plate, double-wall cast-iron plate,
before the beginning of the "mothballed" brick-lined cast-iron plate, cast-iron-and-
period. If repairs cannot be made because steel skeletal. With any of these
of budget constraints, stabilization of the construction types, adequate ventilation in
primary structural components should be the unoccupied lighthouse is essential
first priority, followed by more general during the mothballing period. Adequate
stabilization of the rest of the lighthouse. ventilation will achieve two goals: 1)
Temporary bracing and "splinting" may be minimize excessive heat build-up which
possible techniques for non-structural can damage any sensitive electronic
components. More elaborate shoring may equipment operating inside the tower; 2)
be required to support structural members minimize condensation build-up inside the
that have failed or are in danger of failing. lighthouse (especially brick-lined towers)
For situations where sophisticated structural that can cause the iron to corrode on the
bracing is required, a structural engineer or interior of the tower. In some extreme
historical architect should be consulted for cases minimal heating may be needed to
a proper stabilization treatment plan. The minimize moisture build-up in the
stabilization treatment utilized should not lighthouse. Ventilation of iron towers
permanently damage historic character- through passive and mechanical systems is
defining features and should be easily covered in the Windows section.
reversible so that when the budget allows,
the structure can be properly repaired. For Fire Protection
more information refer to the discussion on
structural stabilization under the repair Despite the fact that iron is
treatment in this section. noncombustible, fire is still a threat to
combustible components of iron
lighthouses and can possibly cause
permanent deformation to the iron
components exposed to intense heat. For
guidance on these issues, refer to "Fire
Prevention and Protection Objectives under
Related Activities in Part VI.
Historic Lighthouse Preservation Handbook Part IV. B, Page 17
Repair
Before any preservation repair work is begun, all iron features that are important in
defining the overall historical character of the lighthouse, such as walls, brackets, cornices,
window architraves, door pediments, steps and pilasters, coatings and color should be
identified. During all repair work it is imperative that measures are taken to ensure that
these features are not damaged or that the action taken will not result in damage to the
feature at a later date. The following are preservation repair treatments for iron lighthouses
and lighthouses with iron components that can be undertaken after a thorough inspection.
Cleaning components. Simple but effective regular
The simple act of cleaning painted iron cleaning will greatly extend the life of the
surfaces can effectively enhance the iron components found on historic
appearance and extend the life of the lighthouses. The following are guidelines
coating. In a marine environment a buildup to follow when cleaning historic iron
of potentially corrosive elements such as lighthouse components:
salts, bird guano, and, in more urban • Clean surfaces only when necessary to remove
locations, industrial pollutants can cause build-up of corrosive agents such as salts,
premature deterioration of iron guano, and industrial pollutants that are causing
damage to iron on the iron coating.
• Clean surfaces with the gentlest method
possible, such as using low pressure water and
mild detergents and natural bristle brushes.
High pressure water blasting may damage
caulking between iron components and force
water into openings, leading to accelerated
w corrosion and deterioration.
Do not use a cleaning method that involves
water or liquid chemical solutions when there is
any possibility of freezing temperatures within
48 hours of treatment.
`y Do not clean with chemical products such as
9^.."
acids that will accelerate the corrosion of the
iron components.
Paint Removal
+ ! When there is extensive failure of the
`. 1r protective coating and/or when heavy
=i corrosion exists, the rust and most or all of
o the paint must be removed to prepare the
a surfaces for new protective coatings. The
techniques available range from physical
3 processes, such as wire brushing and grit
Figure 28. Surfaces such as this sheet-steel-covered blasting, to flame cleaning and chemical
parapet door that are covered with seagull guano should be methods. The selection of an appropriate
thorou_hly cleaned before mothballing and should be
checked and cleaned once a year during the mothballing technique depends upon how much paint
period. failure and corrosion has occurred, the
Part IV. B, Page 18 IRON
fineness of the surface detailing, and the cleaning process will very likely expose
type of new protective coating to be additional coating defects, cracks, and
applied. Local environmental regulations corrosion that were not obvious before.
may restrict the options for cleaning and There are a number of techniques that can
paint removal methods, as well as the
disposal of materials. be used to remove paint and corrosion from
cast iron:
Many of these techniques are potentially Hand scraping, chipping, and wire brushing are
dangerous and should be carried out only the most common and least expensive methods
by experienced and qualified workers using of removing paint and light rust from iron. They
proper protective equipment such as full do not however, remove all corrosion or paint
face respirators, eye protection, protective as effectively as other methods. Experienced
clothing, and Optimum workplace safety craftsmen should carry out the work to reduce
the likelihood that surfaces will be scored or
conditions. Before selecting aprocess test
fragile detail damaged.
panels should be prepared on the iron to be
cleaned to determine the relative Low-pressure grit blasting(commonly called
effectiveness of various techniques. The abrasive cleaning or sandblasting) is often the
SIDEBAR: Paint Removal
I SE5
Tools
- s A variety of hand tools are commercially
%`. o available for the removal of paint from
c = T iron lighthouses. Typically, these tools
. " E are pneumatic or air powered and remove
the paint from the iron substrate with
£ rotating strippers and pulsating rods or
• ;� ; ' u needles. The rotating strippers consist of
{ d a shrouded, spindle-mounted head that
— has 3 or 4 "flaps" outfitted with metal
Figure 29. Worker dressed in full personal protective gear. studs that literally "knock" the paint off
The full-face-shield self-contained respirator provides both
respiratory and eye protection. The worker is wearing the iron surface. Commercially these
protective coveralls,gloves,and boot covers to prevent lead tools are referred to as flush plates. This
dust contact. The harness is part of a full protection system. type of tool is best for the removal of
He is holding a pneumatic needle gun that is hooked to a paint from broad flat surfaces or curved
two-stage HEPA(High Efficiency Particulate Air)filtered
vacuum system. surfaces with a radius of 5 inches or more.
The tools with pulsating rods or needles
typically consist of 12 to 15 hardened metal rods contained in a tube that strike the paint
randomly as they pulsate. This action removes the paint by breaking or crushing it, thus
breaking the bond with the iron substrate. Commercially these tools are referred to as needle
guns or needle scalers. This type of tool is best for reaching tight-detailed locations such as
around gallery deck brackets, etc.
The choice of one of these tools should depend on its impact on the historic iron substrate.
Although iron is very hard, overly aggressive stripping methods can cause irreversible
damage. Stripping tools should be tested in discrete locations to determine their effectiveness
and potential impact on the historic iron substrate. In removing lead-based paint, these types
of tools create both small chips and fine dust. To contain the dust and chips, the tools can be
Historic Lighthouse Preservation Handbook Part IV. B, Page 19
most effectiver
approach to removing excessive Traditionally, the grit or abrasive used was sand.
paint buildup or substantial corrosion. Grit The use of sand for grit blasting has been
blasting is fast, thorough, and economical, and discontinued because of the potential for the
it allows the iron to be cleaned in place. operator to develop silicosis. Today, a variety
Grit blasting is performed by using compressed of grit mediums are available. These grits are
air to blow a grit at a high velocity through a typically derived from mineral slags and are
hand held nozzle. The size and shape of the available in a variety of grades engineered to
grit and the pressure of the compressed air produce the desired surface profile required by
determines the rate at which the paint and various iron and steel paint and coating systems.
underlying substrate (iron or steel in this case) For more delicate applications a variety of
are removed. alternative blast media are available. These
include materials such as walnut shells,
outfitted with dust-collection hoods with
vacuum hookup. As with any paint removal
procedure, personal protective equipment
required for health protection should be worn. d '
Typical personal protective equipment includes
eye/face protection, respiratory protection, f�Ad
gloves, coveralls, hard hat, and protection from
falling if working 6 feet or higher above the
c:' o
ground (see Figure 29). g
n
Figures 30 through 33 are paint removal tools
used during the Sand Key Lighthouse - 3
rehabilitation. Sand Key Lighthouse is located Figure 30.
in open water off the coast of Key West. The
paint being removed contained lead; therefore it
was essential that all debris be contained for
proper disposal.
Figure 30. Clusc-up of a pneumatic needle gun. This tool _
,,orks rrcll for hard-to-reach and detail areas. The needle R's
eon can be presure-controlled to minimize impact on the
iron substrate. This figure shows the vacuum-shroud ' o
connection on the right and air-hose connection on the has t
uf'the pistol-grip handle on the left
Figure 31. The gun is activated by squeezing the lever on `
3
the rubber pistol grip. The amount of air pressure controls Figure 31.
the speed and impact of the pulsating needles against the
iron substrate The needles can be seen protruding from
dtc cuctmm shroud.
Figure 32. Close-tip view of a pneumatic flush-plate tool.
During the Sand Key Lighthouse rehabilitation this tool was
used for all flat surfaces and for removing paint from the
light-tmn cr columns. The rollers located at the top and
bottom of the shroud guide the tool over the Flatand curved -
surfaces. The amount of air pressure controls the speed and
a o
impact of the rotating head against the iron substrate. To t
contain the paint dust and chips,the shroud has been
outfitted with a vacuum hookup. rL
3
Figure 32.
Part IV. B, Page 20 IRON
bicarbonate of soda, and frozen carbon dioxide deep gouging or loss of detailed surfaces, and
(dry ice). the surface profile produced.
When selecting a grit media there are several • Do not use blast pressures above 100 pounds
factors to consider: per square inch (psi). Keeping under 100 psi
• A grit copper slag should be avoided because will still effectively remove the paint and help
of the potential for electrolytic reactions that to minimize damage to the iron substrate.
would corrode the iron surface. • The environmental impact of the residue
• The grit medium should be chosen after produced by the grit medium should be
testing has been performed to determine considered because many lighthouses are
effectiveness of paint removal and potential located in environmentally sensitive areas.
impact or damage to the iron substrate, i.e.,
i A
� t
4 t y ✓ S ,�
Ip ,
:4
O
L s,sy Y
U
Figure 33. Close-up of the studded flaps mounted on the
rotating head. To use the tool, it is held against the face of
the iron member and as the studded P�flaps spin thesla
P Y` "P
the surface and"knock"the paint off the iron.
1
O
e
O
r
* n
t U
c° Figure 35. This motorized chair was used to hoist
workers as they removed paint from the cast-iron
columns at the Sand Key Lighthouse. The chair's motor
is attached to a hoist,so the chair actually climbs a cable
Figure 34. The small vacuums used at Sand Key Light arethat has been strung alongside the column.
shown in this photo. Each vacuum has a HEPA filtration
system to ensure that no lead dust escaped into the
atmosphere. The conditions at Sand Key Lighthouse made
the use of a large central vacuum system impractical. Using
portable vacuums allowed for paint removal at numerous
locations at any one time.
Historic Lighthouse Preservation Handbook Part IV. B, Page 21
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Bender&Associates,Architects
alternative to abrasive blasting for removal of External Coating Systems
heavy paint buildup. These agents are often
available as slow-acting gels or pastes. Because The most common and effective way to
they can cause burns, protective clothing and preserve iron lighthouse components is to
eye protection must be worn. Chemicals maintain a protective paint or coating on
applied to non-watertight, multi-piece features
(such as deck plates or wall plates) can seep the metal.
through crevices and holes, resulting in damage The effective protective life span of an
to the lighthouse's interior finishes and
existing paint or coating can be greatly
corrosion to the backside of the iron
components. If not thoroughly neutralized, increased by routinely touching up areas of
residual traces of cleaning compounds on the deterioration. A small break in the
surface of the iron can cause paint failures in the protective finish can lead to accelerated
future. For these reasons, field application of corrosion of the underlying iron (see Figure
alkaline paint removers and acidic cleaners is 39). Areas where the paint or coating has
not generally recommended. been damaged by mechanical impact or
Following any of these methods of cleaning blistering has occurred should be addressed
and paint removal, the newly cleaned iron immediately. These areas should have all
should be painted immediately with a loose paint and rust scale removed using
corrosion-inhibiting primer to prevent 'flash one of the recommended methods
rusting' from forming. This time period
may vary from minutes to hours dependings
on environmental conditions. Before
application, paint or coating systems may F r
require the iron or steel surface to be wiped .:
with a solvent that removes any
microscopic rust that has formed on the
surface. _
The buildup of salt or chloride residue on
bare metal surfaces will affect the paint or
coating performance. The metal surface
should be tested for chloride buildup from
: .
the salt-laden air found in a marine
environment. If chloride levels are above
levels recommended by the paint or coating
manufacturer, the surface will need to be
wiped with a solvent to remove the
chloride buildup.
If priming is delayed, any surface rust that
has developed should be removed with a o
clean wire brush just before priming. The
rust prevents good bonding between the
primer and the cast-iron surface and may3
Figure 39. The finish on this tension rod failed and
also prevent the primer from completely localized corrosion(rust)has formed. The rust is
filling the pores of the metal. exfoliating in layers that are trapping moisture and causing
corrosion to occur deeper and deeper into the tension rod.
The result is pitting that will compromise the strength of the
tension rod. If the area had been touched up in time,the
corrosion might not have formed.
Historic Lighthouse Preservation Handbook Part IV. B, Page 23
previously described. Hand tool cleaning
and low pressure grit blasting are the most
effective for this scale of paint removal
The bare metal should then be primed and
painted with a primer/top coat system that 0 �.r
will adhere to both the bare metal and the
existing paint or coating system. The top
coat should match the existing color to
maintain the lighthouse daymark.
a
Surface Preparation ;
Figure 40. The paint on this stainless steel replacement
Thorough surface preparation is necessary gallery deck has begun to peel less than three months after
for the adhesion of new protective coatings. it was painted. This could have been prevented if the
All loose, flaking, and deteriorated paint stainless steel parts were first cleaned and then lightly glass-
must be removed from the iron, as well as bead blasted.
dirt and mud, water-soluble salts, oil, and proper profile, the surfaces should be lightly
grease. Old paint that is tightly adhered grit blasted with glass beads to achieve the
may be left on the surface of the iron if it is profile recommended by the manufacturer.
compatible with the proposed coatings.
The retention of old paint also preserves the For the paint to adhere properly, the metal
historic paint sequence of the building and surfaces must be absolutely dry before
avoids the hazards of removal and disposal painting. Unless the paint selected is
of old lead paint. specifically designed for exceptional
It is advisable to consult manufacturer's conditions, painting should not take place
when the temperature is expected to fall
specifications or technical representatives to below 50 degrees Fahrenheit within 24
ensure compatibility between the surface hours or when the relative humidity is
conditions, primer and finish coats, and o
application methods. If the composition of above 80%; paint should not be applied
the existing paint or coating is not known, when there is fog, mist, or rain in the air.
Poorly prepared surfaces will cause the
then a thorough analysis should be failure of even the best paints, while even
performed determine composition the moderately priced paints can be effective if
existing coating to ensure compatibilittyy applied over well-prepared surfaces.
with the future paint or coating. For more
information refer to the Steel Structures
Painting Council publication—Steel Selection of Paints and Coatings
Structures Painting Manual. The types of paints available for protecting
When painting new stainless steel or other iron have changed dramatically in recent
new steel or iron surfaces, special surface years as the result of federal, state, and local
preparation steps must be taken. Typically regulations that prohibit or restrict the
these surfaces have a shop coating of light manufacture and use of products containing
oil applied to prevent rusting. This oil must toxic substances such as lead and zinc
be removed with a solvent before painting. chromate, as well as volatile organic
The surfaces of these materials may not compounds and substances (VOC or VOS).
have the right profile or roughness for the Availability of paint types varies from state
applied coating to adhere. To achieve the to state, and manufacturers continue to
Part IV. B, Page 24 IRON
change product formulations to comply urethane finish coats. Some epoxy coatings
with new regulations. can be used as primers on clean metal or
/
applied to previously painted surfaces in
Traditionally, red lead has been used as an
anti-corrosive pigment for priming iron. sound condition. Epoxies are particularly
susceptible d degradation under ultraviolet
Red lead based paint forms a tough and radiation and
elastic film impervious to water that is must e protected by finish
highly effective as a protective coating for coats which are morre resistant. There have
iron. At least two slow-drying linseed-oil- been problems with epoxy paints which
based finish coats have traditionally been have been shop-applied to iron where the
used over a red lead primer; this coatings have been nicked before
combination is effective e old or partially- installation. Field touch-up of epoxy paints
deteriorated surfaces. is very difficult, if not impossible. This is a
concern since iron exposed by
Today, alkyd paints are very widely used imperfections in the base coat will be more
and have largely replaced lead-containing likely to rust and more frequent
linseed-oil paints. They dry faster than oil maintenance will be required.
paint, with a thinner film, but they do not In recent years, moisture-cured urethane
protect the metal as long. Alkyd rust-
inhibitive primers contain pigments such as coating systems have begun to take the
place of epoxy-based coating systems.
iron oxide, zinc oxide, and zinc phosphate. Moisture-cured urethane coatings are more
These primers are suitable for previously surface tolerant, can be used in lower
painted surfaces cleaned by hand tools. At temperatures, and can be applied and work
least two coats of primer should be applied,
followed by alkyd enamel finish coats. better at higher humidities than epoxy-
based coatings. Moisture-cured urethane
Latex and other water-based paints are not coatings, however, have a tendency to
for use as primers on cast iron or steel thicken quickly under humid conditions
because they cause immediate oxidation if and have the potential of being applied too
applied on bare metal. Vinyl acrylic latex thickly, resulting in a loss of the character-
or acrylic latex paints may be used as finish defining features of the substrate.
coats over alkyd rust-inhibitive primers, but A key factor to take into account in
if the primer coats are imperfectly applied
or are damaged, the latex paint will cause selection of coatings is the variety of
conditions affecting existing and new
oxidation of the iron. Therefore, alkyd
finish coats are recommended over alkyd materials on a particular lighthouse. One
primer may be needed for surfaces with
primer.
existing paint; another for newly cast,
High-performance coatings, such as zinc- chemically stripped, or blast-cleaned cast
rich primers containing zinc dust, urethane iron; and a third for flashing or substitute
based coatings and modern epoxy coatings, materials—all three followed by compatible
can be used on cast iron to provide longer- finish coats.
lasting protection. These coatings typically Another factor to consider when choosing a
require highly clean surfaces and special
application conditions. high performance coating is that these
coatings tend to have a high gloss finish that
One particularly effective system has been is slippery when wet. When painting
developed to coat commercially blast- gallery decks and other iron or steel
cleaned iron with a zinc-rich primer, walkways, anti-skid strips may need to be
followed by an epoxy base coat, and two installed for personnel or visitor safety.
Historic Lighthouse Preservation Handbook Part IV. B, Page 25
SIDEBAR: Masonry and Iron Interaction
A common practice in masonry lighthouse construction is to use iron door and window
hoods, gallery deck brackets, belt courses, and water table caps. These details are both
decorative and structural components of the lighthouse; however, they pose special
preservation issues. The iron that is in contact with the masonry tends to corrode more
readily than the rest of the iron component. This condition is typically evidenced by rust
streaks on the masonry surface (see Figures 41 and 42). This rusting is caused by moisture
either from condensation or precipitation combined with chloride or salt build-up that
collects in the joint. If the joint is not sealed and the coating on the iron is failing, rust will
readily form.
This condition can easily be remedied if the following issues are addressed during the
preservation treatment of the lighthouse. During any repairs or repainting, all masonry and
iron surfaces must be cleaned of all loose paint and rust scale. All mortar that has been
placed between the masonry and the iron should also be removed. The mortar helps trap
moisture against the iron. Once the joint is clean, all exposed iron must be coated with a
tust-inhibiting primer and top coat to provide a barrier between the iron and the mortar.
The void created by the missing mortar should be filled with a new mortar mixture that
matches the strength of the historic mortar (for more information on the matching of
mortar strength refer to the Masonry section). When filling the open joint with the mortar,
hold the mortar back about 1 inch. The joint should then be filled with a /-inch-diameter
polyethylene foam backer rod. To seal the joint, use a high quality silicone or urethane
caulking. (Some caulks may require a painted surface to adhere to brick; therefore, the
surface of the brick that will come in contact with the caulk may have to be painted before
the caulk is applied). Ideally, the caulking depth should equal the joint depth up to a t/2
inch. The profile on the caulking should be slightly concave to shed water. Refer to Figures
43 and 44 for more details.
V. I'
57
0
0
L
p
U
rL
Figure 41 (left). This masonry lighthouse has been detailed
with atwo-tier cast-iron water table(the iron portions are
ail
painted black). Rust-bleed is occurring along lower edge of
the upper tier.
o Figure 42(above).The lower gallery deck of the same
r masonry lighthouse has rust-bleed occurring along the
u lower edge of the iron belt course that supports the gallery
deck brackets.
3
Part IV. B, Page 26 IRON
CAST IRON BELT COURSE
y.^ .
'Y
RAKE OUT LOOSE PAINT, MORTAR, AND
RUST SCALE. PRIME AND PAINT IRON
AND MASONRY (IF PREVIOULY PAINTED
OR REQUIRED BY SEALANT) SURFACES.
SEAL WITH A HIGH QUALITY CAULKING.
Figure 43.
I o
Ii
8 D 8 8 II
II
a
I
II .i
I ,
It
I
:I
I A.
CAST IRON GALLERY
BECK BRACKET I, ,.
U �
CAST IRON BELT COURSE
SEE DETAIL y_ _
- T_L
i L
1'.
MASONRY LIGHTHOUSE
TOWER
Figure 44.
Historic Lighthouse Preservation Handbook Part IV. B, Page 27
Application Methods crumbled from weathering, cracked from
structural settlement, or destroyed by
Brushing is the traditional and most mechanical cleaning. It is essential to
effective technique for applying paint to replace deteriorated caulking to prevent
iron. It provides good contact between the water penetration. For good adhesion and
paint and the iron, as well as the effective performance, an architectural-grade
filling of small pits, cracks, and other polyurethane sealant is preferred. For a
blemishes in the metal. The use of spray more in-depth discussion of various types
guns to apply paint is economical, but does of caulking compounds refer to the
not always produce adequate and uniform Windows section.
coverage. For best results, airless sprayers
should be used by skilled operators. To Water that penetrates the hollow parts of
fully cover fine detailing and reach iron components causes rust that may streak
recesses, spraying of the primer coat, used down over other elements of the
in conjunction with brushing, may be the lighthouse. The water may freeze and the
most effective application method. During expanding ice may crack the cast iron.
application, all overspray must be Cracks reduce the strength of the total cast-
contained; this may be achieved by tenting iron assembly and provide another point of
the lighthouse. Because of the potential for
overspray drift and its environmental '
impact, the industry standard for lighthouse
painting is to use brushes. 5
Rollers should never be used for primer `
coat applications on metal and are effective
for subsequent coats only on large, flat }
areas. The appearance of spray-applied and
roller-applied finish coats is not historically
appropriate and should be avoided on land ,
r
based lighthouses which are viewed up
close by the public. n,
Caulking, Patching, and _ .
Mechanical RepairsF }
�Most iron components on historic
Iighthouses were made of many small
castings assembled by bolts or screws. '
Joints between pieces were caulked to � _ 4f<;, o
prevent water trom seeping in and causing
� U
rustin- from the inside out. Historically, t
O
the seams were often caulked with white Figure 45 Within three months after painting the rust
lead paste and sometimes backed with began to bleed through this weep hole on the bottom of this
cotton or hemp rope; even the bolt and pediment bracket. Two lessons are to be learned from this
screw heads were caulked to protect them condition: 1)keep weep holes open to allow any water that
from the elements and t0 hide them from may have entered the casting to escape,and 2)keepjoints
around applied castings sealed;apparently this was not
view. Although old caulking is sometimes done and water has entered the hollow cavity of the
found in good condition, It is typically pediment,causing rust to form inside.
Part IV. B, Page 28 IRON
entry for water. Water entering seams may Screws with stripped threads and seriously
also cause rust to form within the joint and rusted bolts must be replaced. To
damage the surrounding iron through a compensate for corroded metal around the
process known as 'rust-jacking'. Thus, it is bolt or screw holes, new stainless steel bolts
important that cracks be made weathertight or screws with a larger diameter need to be
by using caulks or fillers, depending on the used. In extreme cases, new holes may
width of the crack:- need to be tapped.
Filler compounds containing iron particles The internal voids of hollow iron lighthouse
in an epoxy resin binder can be used to components should not be filled with
patch superficial, non-structural cracks and concrete; it is an inappropriate treatment
small defects such as rust pits in cast iron. that causes further problems. As the
The thermal expansion rate of epoxy resin concrete cures, it shrinks, leaving a space
alone is different from that of iron, requiring between the concrete and cast iron. Water
the addition of iron particles to ensure penetrating this space does not evaporate
compatibility and to control shrinkage. quickly, thus promoting further rusting.
Although the repaired piece of metal does The corrosion of the iron is further
not have the same strength as a accelerated by the alkaline nature of
homogeneous piece of iron, epoxy-repaired concrete. Where iron components have
members do have some strength. Polyester- been previously filled with concrete, they
based putties, such as those used on auto need to be taken apart, the concrete and
bodies, are also acceptable fillers for small rust removed, and the interior surfaces
holes. For more information on metal paste primed and painted before the components
use in lighthouse restoration, refer to the are reassembled.
Point Bonita Lighthouse rehabilitation case
study in the Part V., Beyond Basic Flashing
Preservation.
In some instances, it may be necessary to
In rare instances, major cracks can be design and install flashing to protect areas
repaired by brazing or welding with special vulnerable to water penetration. Flashings
nickel-alloy welding rods. Brazing or should be designed and fabricated carefully
welding of cast iron is very difficult to carry so that they are effective, as well as
out in the field and should be undertaken unobtrusive in appearance. The most
only by very experienced welders. durable material for flashing iron is terne-
In some cases, mechanical repairs can be coated stainless steel. Other compatible
made to cast iron using iron bars and materials are terne-coated steel and
screws or bolts. In extreme cases, galvanized steel; however, these require
deteriorated cast iron can be cut out and more frequent maintenance and are less
new cast iron spliced in place by welding durable. Copper and lead-coated copper
or brazing. It is frequently less expensive, are not recommended for use as flashing in
however, to replace a deteriorated cast-iron contact with cast iron because of galvanic
section with a new casting rather than to corrosion problems. Galvanic problems
splice or reinforce it. Cast-iron structural can also occur with the use of aluminum if
elements that have failed must either be certain types of electrolytes are present.
reinforced with iron and steel or replaced
entirely.
Historic Lighthouse Preservation Handbook Part IV. B, Page 29
Dismantling and Assembly of Iron be laid out and preassembled to make sure
Components that the alignment and fit are proper. Many
�-
of the original bolts, nuts, and screws may
If repairs cannot be successfully carried out have to be replaced p ed wi h
t similar fasteners of
in place, it is sometimes necessary to stainless steel.
dismantle all or part of a cast iron
lighthouse structure during restoration. After assembly at the site, joints that were
Dismantling should be done only under the historically caulked should be filled with an
direction of a preservation architect or architectural-grade polyurethane sealant or
architectural conservator who is the traditional white lead paste. White lead
experienced with historic cast iron. has the advantage of longevity, although its
Extreme care must be taken since cast iron use is restricted in many areas.
can be brittle, especially in cold weather.
Limited Replacement In Kind
Dismantling should follow the reverse order
of construction and re-erection should The replacement of cast-iron components is
occur, as much as possible, in the exact often the only practical solution when such
order of original assembly. Each piece features are missing, severely corroded, or
should be numbered and keyed to record damaged beyond repair, or where repairs
drawings. When work must be carried out would be only marginally useful in
in cold weather, care needs to be taken to extending the functional life of an iron
avoid fracturing the iron elements by element. For more information on
uneven heating of the members. Both new replacement iron or steel lighthouse
castings and reused pieces should be components refer to the case studies in Part
painted with a shop-applied prime coat on V., Beyond Basic Preservation.
all surfaces. All of the components should
SIDEBAR: Lighthouse Designer/Builder George Meade
General George Gordon Meade is famous to most people as the commander of the Army of
the Potomac which defeated General Robert E. Lee at the Battle of Gettysburg in 1863. But
to lighthouse enthusiasts, Meade is famous for his lighthouse work, specifically Florida Reef
screwpile lighthouses. A screwpile is a screw-like flange located on the end of a lighthouse
foundation pile, which when wound into the substrate, provided greater holding power than
a straight-pile. The first screwpile lighthouse in the United States was at Brandywine Shoal,
Delaware Bay, built by Major Hartman Bache, a distinguished engineer of the Army Corps
of Topographical Engineers. Work began in 1848 and was completed in 1850, with
construction cost at $53,317. Alexander Mitchell, an Englishman who invented the screwpile
principle, served as consultant. The screwpiles were turned by a four-foot capstan worked
by 30 men. Major Bache also built the second screwpile lighthouse in the United States with
construction of the Pungoteague River Lighthouse, Chesapeake Bay, built in 1854.
George Meade was also an engineer in the Army Corps of Topographical Engineers. He
worked with Bache designing and constructing screwpile foundation lighthouses in Delaware
Bay. Meade was also asked to survey and chart the Florida Reefs. The first screwpile skeletal
lighthouse to be built on this dangerous stretch of reefs between Cape Florida and Key West
was the Carysfort Reef Lighthouse, located off Miami and designed by I. W. P. Lewis. The
Part IV. B, Page 30 IRON
a a entire structure was first erected in
�.'S Philadelphia "so as to obviate the
necessity of fitting parts at its isolated
u J a ; • 3 t s*x site." It cost $105,069 to complete.
When the engineer in charge of the
Carysfort Reef Lighthouse project died,
" Meade, now a lieutenant, was assigned the
task of completing the job. This was the
r first of what was to become many
lighthouse jobs for which Meade had
total responsibility. Carysfort Reef
4 Zw 4 Lighthouse was successfully completed in
1 1852. The offshore Carysfort Reef
Lighthouse is believed to be the first
screwpile skeletal tower in the U.S. to use
.. �, foot plates or disks to help disperse the
weight of the tower over a broader
foundation base.
Two months after completing Carysfort
` y r Reef Lighthouse, Meade was asked to
s^ inspect the site selected for the Rebecca
Shoal screwpile lighthouse, also in the
G r a Florida Keys. Meade commented that
i Axa
no beacon of any kind had been erected,
+ " either in the United States or in Europe,
in a position that is more exposed or
x�
offered greater obstacles." His wrought-
iron skeleton light tower was nearly
completed when a three-day storm
completely carried away the structure. A
second attempt was so severely racked by
the pounding seas that the piles worked
out of the sand and it collapsed. The
Lighthouse Board abandoned the
G lighthouse project and marked the shoal
L with buoys.
n
i Meanwhile Meade went on to complete
Figure 46. Bust of George Meade at Barnegat the 132-foot-tall screwpile Sand Key
Lighthouse,Long Beach,New Jersey. Lighthouse to 1853 and the 142-foot-tall
screwpile Sombrero Key Lighthouse in
1858, also in the Florida Keys. One historian stated that Sombrero Key was the most
important lighthouse built by Meade. Meade also designed a five-wick, first-order, hydraulic
lamp which was adopted by the Lighthouse Board in about 1853. Meade was placed in
charge of both the Fourth and Seventh Lighthouse Districts. In 1855 Meade surveyed the
Barnegat Lighthouse, New Jersey, which had received many complaints by mariners. His
suggestion that the tower needed to be replaced with a first-order coastal tower was
approved; the present Barnegat Lighthouse was completed in 1859. Meade also supervised
Historic Lighthouse Preservation Handbook Part IV. B, Page 31
construction of the 167-foot-tall brick Absecon Lighthouse, Atlantic City, New Jersey,
completed in 1857. In 1860 Meade was transferred from Florida to direct the surveys of the
Northern Lakes, but with the advent of the Civil War, Meade requested and received active
military service. He was promoted to brigadier general of the Pennsylvanian Volunteers and
in June 1863 became commander of the Army of the Potomac.
While there are many monuments to George Meade because of his military achievements, few
people are aware of a monument commemorating his lighthouse work. At the base of the
Barnegat Lighthouse is a bronze bust of Meade and a dedication plaque. Ironically, even
fewer people are aware of Meade's most important lighthouse contribution; his work with
Florida Reef screwpile lighthouses.
Part IV. B, Page 32 IRON
e
a a
TI
Figure 26. Detail of handrail that is being deformed by Figure 27. This lantern vent opening has been covered
rust-jacking. with a fine stainless steel screen that prevents insect
infiltration while maximizing air movement through the
vent and into the lantern.
Lantern Glass
cups designed for handling glass, carefully
The lantern glass plays two important roles remove the glass from the frame.
in the lantern system. First, the glass must
be clean and clear to allow the greatest Before the new glass is installed, the channel in
amount of light transmission. Second, the the frame must be completely clear of all old
g putty or sealant and corrosion. Any'hard spot'
glass must be able to withstand high winds, left in the channel could cause a point stress on
driving rain, and airborne material (i.e., the glass, which in turn could cause the glass to
sand and other debris). It is absolutely crack or break.
essential that the glass meet these demands While the glass is out of the iron lantern frame,
at all times. Proper installation care and the iron should be inspected for corrosion. All
replacement will ensure these demands are corrosion that is present must be removed. Any
met. bare iron surfaces should be painted with a
corrosion-resistant coating system.
Lantern Glass Installation When cutting glass to fit, it is imperative that the
• Use only tempered or laminated glass for glass does not touch the frame in any location.
replacement of clear panels. Do not use acrylic This will prevent the glass from breaking when
or polycarbonate for replacement glass; these the lantern frame racks under windy conditions.
materials are easily scratched by airborne sand The glass must rest on either soft wood (pine or
and will fog with time. The glass panes must be cedar) spacers, commercially available Teflon
sized for code-required wind loads and code gasket material (that is approximately 3/16 inch
requirements for glazing next to or above thick), or neoprene setting blocks. The rest of
walking surfaces. In most cases only laminated the glass should be bedded in pressure-sensitive
glass will be acceptable. (Lexan may be more neoprene or butyl-rubber-gasket material
suitable for replacement of colored panels in designed for architectural glass installation.
that they allow more light to pass through than
colored glass.) Install the new glass using handled suction
cups.
• When removing the astragals and clamps that
retain the glass, take care not to damage the Apply the neoprene or butyl-rubber gasket to
screws that hold the members in place. These the outside of the glass and install the astragals
screws are typically made of brass which is and clamps; only snug tighten the screws at first,
relatively soft. then tighten again a few days later to allow the
gasket to set.
• The most effective way to remove the glass is to
cut any paint or sealant away from the glass This system should prevent water from entering
with a sharp knife. Next, using handled suction the window channel and in turn prevent future
damage to the glass from rust-jacking. As an
Historic Lighthouse Preservation Handbook Part IV. G, Page 17
SIDEBAR: Use of Lexan in
Lantern Glass Replacement
In 1986 the wire-glass in the lantern of
the Sombrero Key Lighthouse was
replaced with Lexan (plastic) panels. A
1996 site visit found the Lexan panels
hazed by sunlight and salt air exposure.
This condition greatly reduces the
transmission of light and therefore
reduces the effective range of the aid to
navigation. The inability of the Lexan
panels to withstand the conditions of
the marine environment gives the
panels a short life expectancy when
compared to glass. With these inherent
limitations, Lexan or other plastic
panels should only be used as a
12 temporary repair and not be relied
upon as a long-term lantern glass
material.
3 Sombrero Key Lighthouse is located in
open water in the Gulf of Mexico. In
rsimilar locations that experience
hurricane force winds, laminated glass
has proven successful for the lantern
— glass replacement. Laminated glass is
made by sandwiching a piece of plastic
film between two sheets of tempered
glass. This technology produces a very
durable panel with long lasting clarity
that does not compromise the
effectiveness of the aid to navigation or
impact the historic character of the
lighthouse.
r
Figure 28(top left). Close-up view of severely
hazed Lexan replacement panel. Note the limited
visibility caused by only ten years of sunlight and
t salt air exposure.
Figure 29(bottom left). Looking out through
severely hazed Lexan panels,note the limited
amount of light transmission;this greatly hinders
the effectiveness of the aid to navigation. If the
0
i VV
panels are not replaced,the degradation may
I�I I h n continue and diminish the light transmission,
I ultimately rendering the aid to navigation
3 ineffective.
Part IV. G, Page 18 LANTERN
made. Guttering systems must discharge
rainwater safely to parts of the site which
are designed and maintained to receive
concentrations of water flow.
tl. t
to
yy"t # ,tkp t +iVtiv
Figure 30. Close-up of a first-order lantern that retains its
lantern glass;note the clarity. '�' G
L
Q
added measure, a bead of clear silicone caulk :
may be applied to the exterior side of the g
window/frame joint to shed water away from Figure 31. View of built-in gutter spout on a copper roof.
the joint.
• When curved glass is to replaced, professional
assistance is recommended. Gallery Decks
Lantern Roof In most lighthouses gallery decks are cast-
iron, sheet-metal-covered wood, stone, or
The lantern roof typically serves as the roof concrete. These decks are generally laid
for the entire lighthouse; therefore it is directly on top of the wall structure and act
essential that it and any guttering systems literally as the roof for some portions of the
be weathertight. Traditionally, the lantern lighthouse below. If the decking material
and lighthouse roof (as in the case of the is not weathertight, moisture can enter the
caisson lighthouse) were either terne-coated interior of the lighthouse or lantern.
metal or copper. The roofing was
commonly laid in a standing-seam or flat- When repairing gallery decking, use only like-
kind materials.
seam style. Any metal roofing patches
should be made with like-kind materials • The decking should be sloped away from the
lighthouse to shed the water away from the
soldered in place. If deterioration is structure.
excessive, a new roof which matches the
original in material and configuration
• Inspect all seams for water infiltration: in cast-
should be Considered. iron decking there will be raised corrosion
along the length of the seam; with flat-seam
All rainwater guttering systems (lantern sheet metal there may be a leak present on the
roofs or other tower roof forms) should be interior of the lighthouse; in stone decking there
cleaned and checked for holes. Al holes may be open gaps between the pointing and the
stones.
and non-functioning gutter system
components should be repaired. Holes in r sheet-metal decking should be
repaired
ired with soldered patches or with selective
sheet-metal built-in gutters must be repaired removal and replacement with like-kind
with a properly soldered repair to ensure material; all new seams should be double
the durability of the repair. Caulking locked and soldered.
should be considered only for temporary Cast-iron decking should first have all corrosion
repairs until a proper soldered repair can be removed and the affected surfaces painted with
Historic Lighthouse Preservation Handbook Part IV. G, Page 19
Removal and Application of
Protective Coatings
sem` WARNING: When performing an o the
P f S Y f
>.
following treatments itis essential that the
"• ;.. classical lens and clockworks (if extant) be
-, protected.
As a protective measure and for daymark
purposes, lanterns were historically painted.
r,r As part of a repair treatment, the exterior
coating should be checked for loose and
flaking paint. Any deteriorating areas
t should be scraped and repainted to match
the existing color. Ultimately, as part of
any preservation treatment, the entire
lantern should have all loose and flaking
` paint removed and a new coating applied
C according to the manufacturer's
0
n specifications.
Several factors should be considered when
Figure 32. This sheet-copper-covered lantern gallery deck removing paint from lantern components.
has been repaired several times by soldering sheet copper The combination of ferrous (iron and steel)
patches over the holes. This method of repair, if performed and nonferrous (bronze, brass, copper)
properly,greatly increases the life span of the roof
covering. metals present different challenges when
performing paint removal. As mentioned in
a corrosion-inhibiting coating. The seams the Iron section, paint can be removed
should then be caulked with either butyl-rubber from iron using low-pressure-aggregate blast
or polysulfide caulking. methods and chemical strippers. These
• Some coating systems are very slick when methods can be used on bronze and brass
cured; therefore it is essential that non-skid as well; however the choice of blast media
materials are used on gallery decks that do not and chemicals is different.
already have a non-skid surface texture.
• Deteriorated portions of iron or steel can be Because of the relative softness of bronze,
repaired using metal polymers that can be brass, and copper when compared to iron, a
molded and shaped to match existing textures less aggressive blast media is desirable.
and contours. Walnut shells and bicarbonate of soda are
• Gaps in the joints between stone decking acceptable blast media for bronze, brass,
should be raked out and repointed with a and copper. Before use, the media should
mortar that matches the original in color and be tested in an inconspicuous location at
strength. Damaged stones should be carefully various pressures to determine if the
removed and replaced with like-kind stones. treatment will damage the substrate.
Chemical strippers used on bronze, brass,
or copper should be designed for use on
these metals. Tests should be performed
with the chemical stripper before use on the
Part IV. G, Page 20 LANTERN
entire lantern. The stripper used should not high corrosion resistance and can be left
cause etching or corrosion of the bronze or unpainted to naturally oxidize or patina.
brass substrate. When iron or steel components are to be
Bronze, brass, and copper lantern replaced because of severe deterioration,
components historically may or may not stainless steel should be considered as a
have been painted. These metals will form substitute. Given the complexity of the
a protective oxidized surface coating or issues and the potential application,
however, the selection of the proper grade
patina if not painted. This is the greenish
for use in amarine environment requires
brown tint that is commonly seen on
outdoor bronze sculpture. Brass typically careful evaluation by an engineer.
found on the interior of the lantern,
however, is traditionally kept bright and Installation of Modern Utilities and
shined through regular cleaning and buffing Equipment
by the lighthouse keeper. To maintain a Many historic lighthouses have been
bright shiny finish, the brass may be coated upgraded to either alternating current (AC)
with a finish such as clear lacquer that can or solar power during the conversion to
be applied to maintain this bright automatic operation. During this
appearance (see following sidebar on conversion various pieces of equipment
maintenance of classical lenses). When
painting bronze or brass components on the
exterior of the lantern all surfaces should E
be wiped clean with a metal preparation yx .
k `T
solvent to remove any chloride residue or e9$r £
other contaminants. If chemical strippers
were used, any remaining stripper residue
must be neutralized prior to painting.
For more information on paint application
methods refer to the discussion on paint }
and coating systems in the Iron section.
Limited Replacement In Kind '' f
When replacing all extensively missing or
deteriorating lantern components, such as a l) rjt ; tr
ventilation ball or decorative gutter spout,
the replacement materials need to match
the old materials both physically and
visually, i.e., the metals should not have a
galvanic response.
0
When replacing deteriorated bolts or other
hardware, use matching materials of the 3
highest quality and resistance to the marine Figure
environment. When replacing bronze bolts headboard
rd To minimizese new paneto ls should
wood
beadboard panelling,these new panels should have been
or other elements use Silicon Bronze alloy installed on a sheet ot'plywood attached to the historic
655 or Naval Bronze; both alloys have a wood headboard panelling in tour locations. These
batteries stored on the floor should be in containment boxes
in case the batteries leak.
Historic Lighthouse Preservation Handbook Part IV. G, Page 21
such as electrical panel boxes, conduit,
battery racks, and batteries have been
installed. As this equipment ages or
becomes obsolete, new fixtures may need
to be installed. When installing new a II
utilities and equipment the following factors ILII
should be considered: '
• Use existing openings to run conduit through.
Avoid boring or cutting holes in interior floors
and exterior gallery decks and walls.
• Install electrical panel boxes on plywood panels
that are mounted to the historic walls. This will r a
minimize the impact on interior masonry, iron, IJ
or wood walls. Do not mount panels on built-in
cabinets.
• Attach conduit with clamp or strap-rype
fasteners that do not impact the historic fabric
by use of screws or nails.
• Store batteries in spill-proof boxes that will
contain the liquid battery contents in case of an
accident.
L
n
• Avoid mounting heavy solar panels and °
auxiliary lights on the outside of historic gallery x' 3
deck rails; this will create eccentric loading that Figure 35. This is an acceptable auxiliary light installation.
will ultimately damage the railing. The light is mounted on an aluminum pedestal that has been
• When a classical lens has been converted to AC bolted to the replacement aluminum deck.
or solar power, retain the extant accessories
such as lens jacks, clockwork cranks, wrenches ,:
designed for use with the lens, etc., that were
used for the care and maintenance of the lens.
g
0
r
n
rL
3
Figure 36.This c. 1926 lens was designed to be AC
powered;the original lensjacks are still in place. The three
"N c jacks(the third is obscured by the brass bearing cover)were
used to lift the lens assembly so that bearings could be
serviced.
)
t
l
Figure 34. When this first-order classical lens was
convened to AC power,the original drive gear(pictured
here)was the crank used to wind the clockworks.
Part IV. G, Page 22 LANTERN