facade cleaning

Published on February 2017 | Categories: Documents | Downloads: 28 | Comments: 0 | Views: 162
of 8
Download PDF   Embed   Report

Comments

Content


Richard P.Kadlubowski, AIA and Coleman H.Bynum, AIA,Senior Architects with Hoffmann Architects,oversee
a varietyof façade cleaningprojects for the firm.
Richard P. Kadlubowski, AIA and Coleman H.Bynum, AIA
Journal of architectural
technology published
by H offm ann A rchitects,
specialists in the rehabilitation
of building exteriors.
I S S U E 1/ 2 0 0 1
I
V O L U M E 1 9
I
N U M B E R 1
W
W orkers pressure w ash the concrete
façade of a corporate office building.
>>>> >
(continued onpage2)
Façade Cleaning:
For More Than Appearance’s Sake
hy should a building’s façade be
cleaned? The issue of aesthetics first
com es to m ind. A fter all,a clean building
sim ply looks better than a dirty building. A
clean building presents a m ore hospitable
front—and therefore a m ore attractive
real estate prospect—to the public. Just as
w e put our best foot forw ard w ith a neat,
kem pt appearance,a building looks its best
w hen free of the grim e,pollutants and
staining that shadow its m ost visible—and
often m ost vulnerable—attribute,its
façade.
O f course,not all building façades w arrant
the sam e am ount of care and attention. A
building’s location,function,and geographic
and atm ospheric conditions all play roles
in determ ining the level of cleaning effort
necessary to achieve the desired
appearance.
C onsider function: Structures w hich
house com m ercial activity,in business,
theatre or shopping districts,often w arrant
a higher degree of cleanliness than do
buildings that house industrial—or less
public—activities. A bank building m anager,
for exam ple,m ay choose to m aintain an
im m aculate façade to greet clients and
account holders,w hile a w arehouse
ow ner m ay find it understandably
unnecessary to achieve the sam e level of
cleanliness for his structure.
Furtherm ore,if and w hen it is decided a
building’s façade w ill be cleaned,it m ay
be that only a portion—for instance,
that w hich is visible from the
sidew alk—w ill be cleaned. A
skyscraper in M anhattan,for exam ple,
m ay be cleaned from the ground to
the sixth floors only,lim iting the
cleaning effort to that portion of the
building’s façade that is visible to
bustling com m uters. C leaning the
ground floors only is a viable alternative
w hen it m ay be costly—not to
m ention foolhardy in a pollutant-ridden
urban locale—to clean a building’s
façade com pletely.
Finally,w hat it takes to clean a building
situated in the country is typically far
less an endeavor than if that sam e
building w ere located in a m etropolitan
area. The rural building m ay w arrant
only w ater soaking to rem ove m ild
contam inants (such as dirt),w hile the
urban building w ould m ost likely
require a m ore in-depth cleaning
effort—to rem ove m ore hazardous
pollutants—to achieve the sam e level
of cleanliness.
W hile aesthetics is the obvious—and
prim ary—reason for cleaning a building
façade,the effort to expose the
substrate for evaluation and repair runs
2
J O U R N A L
(continued frompage1)
a close second. It is nearly im possible
to gauge the condition of a m asonry
substrate, for exam ple, w hen the
façade is covered in dirt,grim e and/or
a coating. In order to determ ine
those areas w hich need to be
patched,repaired or resealed—or,in
som e cases,to even properlyidentify
the substrate—the façade should be
cleaned of any and all elem ents that
preclude its proper evaluation.
Still another key m otivation behind
façade cleaning is the effort to
rem ove dam aging pollutants such as
sulfur and nitrogen oxides,and other
acid rain pollutants,from the façade.
These pollutants serve to accelerate
façade deterioration.
C ase in point:m oisture is the prim ary
cause of m asonry decay. W hen
m oisture is coupled w ith soluble salts
from polluted rainw aters or w ith
atm ospheric gases,the decay is
accelerated. W hen the soluble salt
dissolves in w ater,it travels deep into
the m asonry substrate through pores
or cracks. O nce the m oisture
evaporates,the salt recrystallizes,
exerting trem endous pressures w hich
break dow n the m asonry from w ithin.
A dditionally,atm ospheric gases such
as carbon dioxide,sulfur dioxide and
nitrogen oxides react w ith dirty,w et
surfaces to form corrosive liquids such
as carbonic acid,sulfuric acid and nitric
acid. These liquids react w ith various
elem ents in the m asonry and m ay
result in the form ation of hardened
surface crusts and dissolution of acid-
soluble cem enting binders that hold
the m asonry together. The form ation
of these dense surface crusts and the
w ashing aw ay of acid-soluble binders,
if allow ed to persist,are progressive
deterioration processes.
Lastly,façade cleaning opens a building’s
pores and allow s the norm al
transpiration of m oisture. M oisture
trapped w ithin a m asonry w all,for
exam ple, w ill rem ain there if a
w aterproofing coating prevents its exit. In
this case, as m oisture is the leading cause
of m asonry decay,com prehensive façade
cleaning to include rem oval of the
w aterproofing coating m ay be the key
com ponent of the design professional’s
effort to restore the building.
How Clean is Clean Enough?
O nce the decision has been m ade to
clean a building’s façade,the question of
‘how clean is clean enough?’m ay arise.
G enerally,the prim ary objective should
be to rem ove any and all contam inants
from the façade. Beyond this,the
question of ‘how clean is clean enough?’
should be answ ered on a case-by-case
basis, w ith the full subjectivity of the
building ow ner and/or m anager.
In the case of older buildings,how ever,
should they be so thoroughly cleaned as
to look new ? W ould the Pantheon in
Rom e suffer in our m ind’s eye if its 1800-
year history w ere som ew hat forgotten in
the gleam of pristinely scrubbed
pozzolan
1
concrete? Indeed,m any
individuals involved w ith the preservation
of historic structures argue that too
m uch cleaning strips these buildings of “a
certain dignity earned w ith the passage
of tim e.”
2
They assert that the dirt patina
represents a natural process of
w eathering w hich is of “im portant
historical significance and in character
w ith older buildings view ed in a
contem porary setting.”
2
H ow ever,the fact rem ains that the
accum ulation of surface staining goes far
beyond aesthetic deform ation;heavy
surface deposits contribute to the
progressive decay of stone,m asonry and
concrete surfaces. The ow ner,w ith the
guidance of the design professional, m ust
find a balance for the building’s façade at
w hich point it is free of any contam inants
that m ay threaten the substrate w hile not
so scrubbed as to contradict the
structure’s history.
To Clean Before or After Restoration/
Repairs?
Still another im portant factor to
consider in preparing to clean a building
façade is when to do it: before or after
repairs and restoration w ork. A s
previously m entioned,it can be difficult
to detect w hat m ay need to be repaired
in a surface w hen it is heavily coated in
dirt,stains,paint and/or other coatings.
A nd, as it is best to patch/repair a clean,
sound surface,it m ay be preferable to
clean the façade before any repairs.
H ow ever,there are exceptions to this
som ew hat loose rule. For exam ple,
w hen a stone building has extensive leak
problem s,and the design professional
m ust coordinate patching and sealant
w ork,it m ay very w ell be a m istake to
run the risk of even greater w ater
intrusion by adding w ater during
cleaning to already precarious areas. In
these instances,the design professional
m ay choose to patch and seal areas of
w ater intrusion prior to the
com m encem ent of cleaning.
Protection Against Damage
To ensure a successful façade cleaning
project,w hether it be for stone and
m asonry,concrete,or alum inum ,it is
crucial to choose and im plem ent the
m ost appropriate m ethod for the
surface. Protection against dam age to
personnel,to the building,to the site and
to the environm ent should be the
forem ost consideration in choosing and
im plem enting the cleaning m ethod.
1
pozzolan: The Romans produced lime byburninglimestone pieces. Mixed with volcanic ash (pozzolan) and water,it becomes a mortar. The Romans mixed
this mortar with small stones, bricks and other materials to produce concrete.
3
V O L U M E 1 9
I
N U M B E R 1
(continued onpage4)
Protecting personnel Protecting personnel Protecting personnel Protecting personnel Protecting personnel
O f the three general categories of
cleaning m ethods—chem ical cleaning,
w ater cleaning and abrasive cleaning—
chem ical cleaning packs the highest risk
quotient to the individual. The design
professional should require as part of
the cleaning subm ittals a detailed
description of the proposed m aterials
and m ethods of protection for
preventing harm caused by the cleaning
w ork to all persons in the cleaning area.
Product data and M aterial Safety D ata
Sheets (M SD S) should be subm itted for
all recom m ended m aterials and chem ical
cleaning products.
The persons perform ing the cleaning
m ust adhere to the guidelines set forth
in a chem ical’s M SD S to protect against
dam age to them selves or the public. A ll
precautionary m easures should be read
carefully,and first-aid instructions—in
case of contact or exposure—should be
review ed. These instructions include
w hat to do in case of eye contact,skin
contact,inhalation and ingestion. A lso
included in the M SD S are spill and leak
procedures as w ell as guidelines for
container handling,storage and shelf life.
C hem ical cleaning products are not the
only potentially hazardous elem ents to
be aw are of during façade cleaning. Bird
droppings and other bird-related m atter
offer another source of som e very
unhealthy effects. A nd,as one can w ell
im agine,there is a distinct possibility that
one w ill encounter a considerable
am ount of bird m atter during façade
cleaning.
Bird droppings and other bird-related
m atter contain substances, including
agents of diseases such as Histoplasmosis
and Cryptococcosis,that are harm ful—
and som etim es fatal—to hum ans. A ll
necessary precautions m ust be taken to
prevent w orkers and other people
w ithout appropriate protection from
touching, ingesting, inhaling or contacting
in any other w ay bird-related m atter.
Finally,the disposal of such substances
m ust com ply w ith applicable federal, state
and local law s and regulations.
Protecting the building Protecting the building Protecting the building Protecting the building Protecting the building
In protecting against dam age to the
building during façade cleaning,the
design professional should subm it in
advance a detailed description,including
draw ings and diagram s,of proposed
m aterials and m ethods of protection for
preventing harm ,dam age or
deterioration caused by the cleaning
w ork to all building elem ents,m aterials
and finishes.
To protect surfaces of the building
intended to rem ain w ithout cleaning, the
design professional instructs the
contractor as to the specified protection
m aterials to protect all glass,m etal,w ood
and/or painted surfaces that should not
be affected during m asonry cleaning,for
exam ple. These specified protection
m aterials m ay include m asking products
that are som etim es part of a
m anufacturer’s chem ical cleaning system .
A dditionally,all w indow s and doors and
other existing openings should be
tem porarily sealed to prevent liquid and
particulate entry. A gain,m aterials used
to do this m ust be those specified by the
design professional. W indow and door
hardw are should be checked for
operability at the conclusion of the w ork.
Test cleaning a patch of the façade is a
critical elem ent of the façade cleaning
process.It is essential not only in
ensuring that the cleaning effort w ill have
the desired results but also in ensuring
that the chosen m ethod w ill not dam age
the façade. Prior to initiating a full
m asonry cleaning project,for exam ple,
test cleaning should be conducted for
100 square feet for each substrate
and for each cleaning m ethod
specified. Full cleaning should not
proceed until the test patch has been
review ed and accepted by the design
professional and the building ow ner.
Prior to test cleaning,it m ust be
assured that the w ork of other trades
that m ight affect the cleaning w ork is
fully com plete. C leaning should not
com m ence until all other w ork has
ceased. W hen perform ing the test
patch,only the cleaning m ethods
specified by the design professional
for each type of m aterial and location
should be used. Each cleaning
m ethod indicated should be
perform ed in a m anner w hich results
in uniform coverage of all surfaces,
2
Boyer,David.W., Author,“MasonryCleaning-The State of the Art,”CleaningStone and Masonry. 1986.
End of a copper joint cover is open in a
joint in a projecting course.
Points of w ater infiltration that should be
repaired prior to façade cleaning:
Lead joint cover has been pushed out
of the joint. C aulking in joint is brittle
and not bonded to the stone.
>> >>>
>> >>>
4
J O U R N A L
including corners and m oldings,and
w hich produces an even effect w ithout
streaking or dam age to the surface.
Finally,planning around M other
N ature is essential in protecting
against dam age to the building during
façade cleaning. The w eather can
m ake or break a façade cleaning
project. If it is too cold, liquid cleaning
products and w ater w ill freeze to
sheets of ice. C onversely,if it is too
w arm ,a chem ical product’s drying
tim e m ay accelerate,so it m ay not
have tim e to w ork as it should and
m ay not w ash off properly.
Furtherm ore,w ind m ay cause
additional problem s w ith vapor and
overspray. The design professional
should specify stipulations on how to
w ork around the w eather prior to
com m encem ent of the façade cleaning
project (i.e., A cleaning specification m ay
require that m asonry cleaning w ork not
be perform ed w hen tem peratures m ay
drop below 50 degrees-or soar above
90 degrees-Fahrenheit w ithin 24 hours of
the w ork.).
Protecting the site Protecting the site Protecting the site Protecting the site Protecting the site
To protect the site during façade
cleaning,plans m ust be im plem ented to
confine dust,liquids,overspray and debris
to prevent detrim ental effects to
adjacent properties and to the public.
Tem porary protection such as barriers,
enclosures, netting or other protection
as needed should be provided and
erected to prevent harm to personnel
and adjacent portions of the building.
O nce the w ork of the cleaning operations
has ceased,all tem porary protection
should be rem oved.
Furtherm ore,the design professional
should ensure m inim um interference
w ith streets, w alks and other adjacent
facilities. For exam ple,the flow of w ater
from soaking and cleaning operations
should be continuously m onitored to
avoid dam age to the building and
surrounding areas,and excessive
am ounts of w ater should not be
perm itted to flow across w alkw ays. A lso,
plyw ood trafficw ays m ay be necessary
for all surfaces such as roofs or terraces
that w ill receive pedestrian traffic during
cleaning. The plyw ood should be free of
splinters,fasteners and any other
irregularities that m ay dam age the
existing surface.
Protecting the en Protecting the en Protecting the en Protecting the en Protecting the environment vironment vironment vironment vironment
The design professional should plan in
advance any necessary precautions to
prevent hazardous m aterial from
entering the environm ent. A ll m eans
necessary should be utilized to prevent
contam inated w ater,chem icals,chem ical
fum es and abrasive particles from flow ing
into drains or entering air intakes and
exhausts. Protection and w aste
collection system s should be in place
before general cleaning begins.
To prevent cleaning chem icals or
particles of dirt or m ortar from flow ing
into drains,for exam ple,the design
professional m ay instruct that
appropriate precautions be taken.
CleaningStone, Masonry and
Architectural Concrete
Basically,all façade cleaning projects fall
into one of four categories: chem ical,
non-chem ical,abrasive and those that
m ay require a com bination of these
m ethods. For exam ple,though a
W ater soaking is one of the least intrusive
façade cleaning m ethods:
(Left) W ater-soaking nozzles assem bled
to clean a lim estone façade.
(Below) A w orker scrubs and rem oves
softened soil from the w ater-soaked
lim estone façade.
>> >> >
>>>> >
(continued frompage3)
5
V O L U M E 1 9
I
N U M B E R 1
(continued onpage7)
m asonry façade cleaning project m ay
partially succeed w ith a non-chem ical
w ater soaking procedure to loosen dirt
and w ash it aw ay,it m ay be necessary to
supplem ent this m ethod w ith an
appropriate cleaning agent (chem ical) to
treat areas of heavy stains.
The building ow ner and/or m anager
should consult w ith the design
professional to arrive at the façade
cleaning m ethod that is best suited to
their building.
W WW WWater cleaning methods ater cleaning methods ater cleaning methods ater cleaning methods ater cleaning methods
W WW WW ater Soaking: ater Soaking: ater Soaking: ater Soaking: ater Soaking: A slow,steady stream of
w ater
3
is used to loosen dirt and w ash it
aw ay,a very effective m ethod as the dirt
becom es sw ollen and soft. A m anifold of
piping and nozzles is constructed for this
purpose. H and scrubbing w ith brushes
or rinsing w ith 400 psi (pounds per
square inch) w ater spray m ay follow the
w ater soaking.
For each w ater soaking façade cleaning
project,the design professional
determ ines the appropriate:
a) duration of soaking (in hours);
b) num ber of gallons of w ater per
m inute per nozzle;and
c) nozzle spacing.
This m ethod is very effective on stone,
especially lim estone,and glazed brick.
H ow ever,there are possible lim itations
related to this procedure—as there are
w ith any procedure—that m ust be taken
into consideration:
· Prolonged exposure results in oxidation
of natural com ponents of m asonry and
transports harm ful salts deep into the
m asonry.
· Saturated m asonry takes several w eeks
to dry.
· C leaning of the m asonry façade m ust
be scheduled for tim es w hen there is
no threat of freezing.
· C ontinuous cascading of w ater
results in erosion.
· There exists the possibility that
interior surfaces, furnishings and
equipm ent m ay be dam aged.
· W ater run-off m ust be controlled.
Pressure Pressure Pressure Pressure Pressure W WW WW ashing: ashing: ashing: ashing: ashing: Pressurized w ater,
m easured in pounds per square inch
(psi),blasts contam inants aw ay from
the façade. This procedure is effective
on stone,m asonry and concrete for
the rem oval of light to m oderate
atm ospheric and organic staining. This
m ethod utilizing heated w ater (not to
exceed 160 degrees Fahrenheit) m ay
prove effective for rem oval of grease
and oil stains.
Som etim es referred to as pow er
w ashing,pressure w ashing is specified
by the design professional according to
four param eters:
a) pressure rating (psi);
b) w ater flow rate;
c) spray tip (type and size);and
d) distance from the substrate.
Lim itations associated w ith this
procedure are as follow s:
· Pressure w ashing alone w ill not
rem ove severe staining.
· H igh pressures are abrasive and m ay
partially rem ove m ortar and etch
stone.
· O xidation of m asonry m ay result.
· Saturated m asonry takes several
w eeks to dry.
· C leaning m ust be scheduled w hen there
is no threat of freezing.
· W ater m ay find its w ay through sm all
openings and cause prem ature decay.
· W ater run-off m ust be controlled.
· This m ethod is not a replacem ent for
hand labor.
· This m ethod should N O T be used to
apply chem ical cleaners,as the chem icals
w ill be driven deep into the m asonry.
Chemical cleaning methods Chemical cleaning methods Chemical cleaning methods Chemical cleaning methods Chemical cleaning methods
M anufactured by com panies to conquer
the “tough”façade stains,chem ical
cleaning products w ork by dissolving the
stains,allow ing them to be rinsed aw ay.
G enerally,chem ical cleaners fall into one
of four categories: acidic cleaners,alkaline
cleaners,organic solvents,and special non-
sudsingdetergents.
The list of available com m ercial chem ical
cleaners for different types of façade
surfaces is long and varied: Som e are
designed to rem ove efflorescence and salt
staining. O thers are used prim arily to
rem ove excess m ortar,grout stains and
dirt. Still others are best suited for use on
brick that m ay have high m etallic content.
There are restoration cleaners designed
to com bat extrem ely dirty and heavily
carboned m asonry typically found in large
cities or high pollution areas. C om m ercial
poultices,designed for areas in w hich the
contam inant has penetrated into the
substrate,as opposed to being on the
surface,are available for different types of
surfaces. Strippable m asking m aterials are
available to protect glass,m etal and
polished stone surfaces from the
dam aging effects of acidic brick cleaners.
A s is evidenced by the aforem entioned
exam ples, chem ical products are
3
Water for façade cleaningshould be fromthe municipal water supplyand clean at the time of use. In some cases,the water used for cleaning
buildingfaçades mayneed to be pre-treated with an ion-exchange water softeningsystemin order to avoid staining,efflorescence and other
problems.
6
J O U R N A L
Radio City Music Hall at Rockefeller Center
N ew York,N ew York (Rockefeller C enter M anagem ent C orporation)
Our Lady of Angels Motherhouse and Chapel Enfield,C onnecticut.
Façade C leaning Façade C leaning Façade C leaning Façade C leaning Façade C leaning
H offm ann A rchitects has developed and
im plem ented façade cleaning program s
for a num ber of its clients. The follow ing
narratives briefly discuss the diverse
plans prepared for som e of these clients.
Rock Rock Rock Rock Rockef ef ef ef efeller C enter eller C enter eller C enter eller C enter eller C enter
N ew York,N ew York
(Rockefeller C enter M anagem ent
C orporation)
A s part of an overall rehabilitation plan,
the design professionals of H offm ann
A rchitects im plem ented w ater soaking
follow ed by scrubbing w ith brushes to
clean the Indiana Lim estone façades of
the landm ark Rockefeller C enter
com plex.The w ater soaking,w hich did
not threaten to etch the stone,w as
initiated after repairs so as not to allow
w ater to enter open joints. A bsolutely
no chem icals w ere used during the
cleaning process.
H offm ann A rchitects scheduled the
cleaning w ork so as not to im pede the
pedestrian traffic along the busy block
that lies betw een N ew York C ity’s 5th
and 6th Avenues and 48th and 51st
Streets—and so that w ater runoff did
not pose any problem s. M ost of the
cleaning w ork w as therefore com pleted
during the night w hen relatively few
people w ere in the area.
Souther Souther Souther Souther Southern N ew England n N ew England n N ew England n N ew England n N ew England T TT TTelephone elephone elephone elephone elephone
(SN ET) (SN ET) (SN ET) (SN ET) (SN ET)
H artford,C onnecticut
H offm ann A rchitects initiated a repair
and cleaning effort to rehabilitate the
lim estone façades at SN ET’s H artford
facility.
A com bination of chem ical and non-
chem ical m ethods w as used to
achieve the desired cleaning results
for the structure. The cleaning effort
began w ith long periods of w ater
soaking (12- to 24-hour soaks)
follow ed by scrubbing w ith clean,
natural bristle brushes to rem ove
H offm ann A rchitects
cleaned the facades of existing w ater repellents to enable the brickw ork to breathe.
>> >>>
>> >>>
V O L U M E 1 9
I
N U M B E R 1
7
(continued onpage8)
(continued frompage5)
C hr C hr C hr C hr C hrysler Building ysler Building ysler Building ysler Building ysler Building
N ew York,N ew York
250 Broadw a 250 Broadw a 250 Broadw a 250 Broadw a 250 Broadw ay yy yy
N ew York,N ew York
stains. Lastly,a chem ical cleaning
product w as used to rem ove heavy
stains.
The Pr The Pr The Pr The Pr The Prudential Insur udential Insur udential Insur udential Insur udential Insurance C om pan ance C om pan ance C om pan ance C om pan ance C om pany yy yy
of of of of of A m er A m er A m er A m er A m erica ica ica ica ica
Easter Easter Easter Easter Eastern O per n O per n O per n O per n O perations O ff ations O ff ations O ff ations O ff ations O ffice ice ice ice ice
D resher,Pennsylvania
A s part of a com prehensive restora-
tion effort,H offm ann A rchitects
im plem ented a plan to clean the
concrete façades of Prudential’s
Eastern O perations O ffice. N o
chem icals w ere used during the
cleaning process. To ensure successful
results during pressure w ashing of the
facade,consistent param eters—for
type and size of tip,pressure rating
(psi),w ater flow rate and distance from
the substrate—w ere m aintained from
the beginning to the end of the project.
C hase M anhattan C entre C hase M anhattan C entre C hase M anhattan C entre C hase M anhattan C entre C hase M anhattan C entre
1201 M arket Street
W ilm ington, D E
H offm ann A rchitects utilized a
com bination of m ethods to clean the
polished granite and concrete facades
of C hase M anhattan’s one-block-square
office com plex.
Both the polished granite w ater table
and the concrete façades w ere w ater
soaked for 12- to 24-hour periods.
The w ater table w as further low -
pressure w ashed at tw o to four
hundred psi. A reas of heavy stains—
such as the concrete above the loading
dock that carried the exhaust from
countless trucks—w ere treated w ith a
chem ical cleaning agent.
V VV VVassar C ollege assar C ollege assar C ollege assar C ollege assar C ollege
V VV VVassar O bser assar O bser assar O bser assar O bser assar O bservator vator vator vator vatory yy yy
Poughkeepsie,N ew York
C ongregation Rodeph Sholom C ongregation Rodeph Sholom C ongregation Rodeph Sholom C ongregation Rodeph Sholom C ongregation Rodeph Sholom
Bridgeport,C onnecticut
N ew N ew N ew N ew N ew Y YY YYor or or or ork Stock Exchange k Stock Exchange k Stock Exchange k Stock Exchange k Stock Exchange
N ew York,N ew York
V VV VVer er er er eriz iz iz iz izon C om m on C om m on C om m on C om m on C om m unications unications unications unications unications
N ew York,N ew York
X ero X ero X ero X ero X erox C or x C or x C or x C or x C orpor por por por poration ation ation ation ation
C or C or C or C or C orpor por por por porate H eadquar ate H eadquar ate H eadquar ate H eadquar ate H eadquarter ter ter ter ters ss ss
Stam ford,C onnecticut
X ero X ero X ero X ero X erox D ocum ent U niv x D ocum ent U niv x D ocum ent U niv x D ocum ent U niv x D ocum ent U niver er er er ersity sity sity sity sity
Leesburg,Virginia
U nited States C apitol U nited States C apitol U nited States C apitol U nited States C apitol U nited States C apitol
W ashington,D istrict of C olum bia
(The A rchitect of the C apitol)
Fred French Building Fred French Building Fred French Building Fred French Building Fred French Building
551 Fifth Avenue
N ew York,N ew York
(M etropolitan Life Insurance C om pany)
O ur Lady of O ur Lady of O ur Lady of O ur Lady of O ur Lady of A ngels M otherhouse and A ngels M otherhouse and A ngels M otherhouse and A ngels M otherhouse and A ngels M otherhouse and
C hapel C hapel C hapel C hapel C hapel
Enfield,C onnecticut
(Felician Sisters of the O rder of St.
Francis)
M etLife Building M etLife Building M etLife Building M etLife Building M etLife Building
N ew York,N ew York
(M etropolitan Life Insurance C om pany)
Handling of cleaning wastewater Handling of cleaning wastewater Handling of cleaning wastewater Handling of cleaning wastewater Handling of cleaning wastewater
The runoff from chem ical cleaning and
rinsing operations falls into three
categories: non-hazardous w astew ater,
acidic/alkaline w astew ater that can be
neutralized on site,and w astew ater
classified as special or hazardous w aste.
N on-hazardous w astew ater m ay be
released to sanitary sew ers,storm
sew ers,or by soaking into the ground.
A cidic/alkaline w astew ater m ust be
contained and neutralized prior to
release to sanitary sew ers—it should
never be released to storm sew ers per
Environm ental Protection A gency (EPA )
regulations;the design professional
should verify in advance the “industrial
w astew ater pretreatm ent program ”of
the m unicipality.
H azardous w astew ater that contains
com pounds such as m ethylene chloride
(a paint stripper) m ust be contained,
pum ped into storage tanks and taken to
a licensed Transport,Storage and
D isposal (TSD ) facility.
Abr Abr Abr Abr Abrasive cleaning methods asive cleaning methods asive cleaning methods asive cleaning methods asive cleaning methods
O f the various m ethods to clean stone,
m asonry and concrete,abrasive cleaning
is unique in that it is designed to
com pletely rem ove the outer portion of
the substrate on w hich the stain sits,
rather than m erely dissolving and
w ashing aw ay the stain. For this reason,
m anufacturer’s guidelines outlined in the
M aterial Safety D ata Sheets w hen
im plem enting a chem ical façade cleaning
m ethod. H andling and storage,clean-up
and disposal,and safety and first-aid
inform ation should be review ed in
advance.
Other F Other F Other F Other F Other Façade Cleaning Projects: açade Cleaning Projects: açade Cleaning Projects: açade Cleaning Projects: açade Cleaning Projects:
The H ar The H ar The H ar The H ar The H artf tf tf tf tford Insur ord Insur ord Insur ord Insur ord Insurance C om pan ance C om pan ance C om pan ance C om pan ance C om pany yy yy
C or C or C or C or C orpor por por por porate H eadquar ate H eadquar ate H eadquar ate H eadquar ate H eadquarter ter ter ter ters ss ss
H artford,C onnecticut
M attatuck M useum M attatuck M useum M attatuck M useum M attatuck M useum M attatuck M useum
(Bank of Boston Building) (Bank of Boston Building) (Bank of Boston Building) (Bank of Boston Building) (Bank of Boston Building)
W aterbury,C onnecticut
num erous and designed to solve a variety
of cleaning issues. It is essential to follow
the design professional’s guidelines set
forth in the subm ittals and the
432 W ashington Avenue
N orth H aven,C onnecticut 06473
A D D RESS SERVIC E REQ U ESTED
JOURNAL is a publication of H offm ann
A rchitects, specialists in the
rehabilitation of building exteriors.
The firm ’s w ork includes investigative and
rehabilitative architecture/engineering
services for the analysis
and resolution of problem s w ithin
roofs,facades,glazing,and structural
system s of existing buildings,plazas/
terraces,and parking garages.
Please send new s,technical inform ation,
address changes,or requests for free
subscriptions to Editor,H offm ann
A rchitects JOURNAL,432 W ashington
Avenue,N orth H aven,C onnecticut
06473.For answ ers to specific questions
or for inform ation on the services
H offm ann A rchitects offers,please contact
Sandra M atheny at
(203) 239-6660.
432 W ashington Avenue
N orth H aven C T 06473-1309
203 239-6660
500 Fifth Avenue,Suite 830
N ew York N Y 10110-0899
212 789-9915
1001 C onnecticut Avenue N W
W ashington D C 20036-5525
202 530-1100
For more information on the
topics discussed in this article,
visit us on the web at
www.hoffmannarchitects.com,
or contact us at
[email protected].
Editor:M aryellen A pelquist
G raphic Services:M aryellen A pelquist
PRSRT STD
U .S.PO STAG E
PA ID
PERM IT N O .1090
N EW H AVEN ,C T
J O U R N A L
(continued frompage7)
intrusive to the substrate. W hile
abrasive cleaning m ethods are
effective in rem oving a variety of
surface stains, the lim itations associ-
ated w ith the various techniques are
num erous:
· Rem oval of m asonry surface
exposes a softer substrate to m ore
rapid deterioration.
· A brasive cleaning techniques are
ineffective in rem oval of subsurface
staining.
· The significant am ount of dust
created by abrasive techniques m akes
the m onitoring of progress difficult.
· A irborne silica dust present safety
hazards;sandblasting is banned in
m any m unicipalities.
· A brasive cleaning opens the surface
area of the treated substrate to
atm ospheric corrosion, w ater
CleaningAluminum
C leaning architectural alum inum is a
relatively sim ple process. A s the strength
and durability of alum inum is not
m aterially affected by dirt or oxidation,
cleaning is generally necessary only as an
aesthetic m easure. Therefore,the
frequency of cleaning is prim arily
determ ined by the desired appearance
of the structure. O ther m aintenance
w ith w hich alum inum cleaning m ay be
conveniently com bined and local
atm ospheric conditions also play roles in
determ ining the frequency of alum inum
façade cleaning.
M ild cleaners,solvent and em ulsion
cleaners, abrasive and etching cleaners,
steam cleaners and pow er-driven
brushes are am ong the m ethods used to
clean alum inum façades. The building
ow ner and/or m anager should consult
w ith the design professional to arrive at
the alum inum façade cleaning m ethod
that is best suited to their building.
C leaner concentration and application
tim e instructions,as w ell as the
m anufacturer’s safety precautions,should
be follow ed carefully to ensure a safe and
effective façade cleaning project.
recom m ended for restorative facade
cleaning projects. G rit blasting,
grinding w heels,sanding disks,sanding
belts and w et sandblasting (grit
blasting com bined w ith high pressure
w ashing) all fall into the category of
abrasive cleaning. N ew m ethods,
using very sm all (20- to 100- m icron)
grit and containm ent of the cleaning
area,are available w hich are far less
absorption and other decay processes.
· G rit blasting m ay increase the need for
repointing.
abrasive cleaning is generally not

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close