Compliance and Safety at a Metal
Fabrication Shop
Jeff Stubbs
(603) 749-9904
X-L Corp. and Spraytek Corp.
25 Progress Ave
Nashua, NH 03062
contact: Bob Fay
(603) 889-0232
EXECUTIVE SUMMARY
There are a few different projects that I worked on at X-L and Spraytek. The
major project and the one that I spent most of my time on dealt with cleaning the parts
prior to cleaning. Spraytek now uses trichloroethylene (TCE) in a vapor degreaser to
clean their parts. Since TCE is listed as a hazardous air pollutant (HAP) by the Clean
Air Act Amendments of 1990 (CAAA) its use will be regulated strictly as of Dec. 2,
1997. To prepare Spraytek for these new regulations I have determined several options
that will allow Spraytek to ensure that they will be in compliance. These options are to
1) install some new control devices on the degreaser to reduce the emissions or 2)use an
alkaline aqueous cleaner to replace TCE in parts cleaning or 3) replace TCE with an
aqueous cleaning/phosphating solution. The project results section of this report lists
each of these options, what is involved with each option and the advantages and
disadvantages of each option.
Some other projects I have been working on deal with aluminum dust collection
and disposal, improving the cleanliness and safety in lead working operations, and
obtaining a permit for the recently installed chrome plating line. The aluminum dust
disposal problem pertains to sludge from a wet type dust collector that is a mixture of
steel, stainless steel and aluminum dusts and water. If the sludge is too wet when it is
put into the 55 gallon disposal drums a reaction between the aluminum and water gives
off hydrogen gas and heat. This causes the drums to get smoldering hot and can remain
that way for days. To avoid this the sludge is now allowed to dry out on screens before
being put into the drums. The sludge is then sent to a company in Louisiana who uses it
in mixing cement. The lead working operations are confined to one room ( the "lead
room") to reduce employee exposure. Aluminum and lead dusts accumulate on tables
and floors in the lead room. This causes health and safety considerations because lead is
a health hazard and aluminum dust is explosive when stirred up into a cloud. X-L has
two options in this case. One option is to purchase an expensive explosion proof
vacuum that is equipped with a HEPA filter to clean up both types of dusts. Another
option is to eliminate the creation of aluminum dust in the lead room so that a standard
vacuum with a HEPA filter can be used to clean the lead room. I have also completed
the limited permit application form for the chrome plating line. When they receive the
results of a TCLP analysis for metals for the wastewater stream that is put into the
evaporator X-L will send this along with the application form to the Waste Management
Division at the DES.
INTRODUCTION
X-L and Spraytek Corporations run a small sheet metal fabrication operation in
which they produce a variety of metal parts. The two companies are located next door
to each other in the same building. Most of the parts that are made at X-L are painted
by Spraytek. Spraytek also does jobs for other companies. In order to comply with
regulations and increase the safety of their facility they are interested in changing the
way certain steps are performed during the production process.
The major project that I worked on dealt with the degreasing step during the
preparation of the parts for painting. Spraytek now uses TCE in a vapor degreaser to
clean the parts. After cleaning the parts are primed using a wash primer. This step
gives the parts a coating that ensures that the paint will adhere well to the parts. The
parts that are being cleaned are steel, stainless steel and aluminum and range in size
from small parts that would be loaded into a basket to large beams that actually extend
out of the top of the degreaser. The contaminants that need to be removed from the
parts are mainly cutting oils and coolants (both water soluble and non-water soluble),
grease and fingerprints. TCE has been designated a HAP and as of Dec. 2, 1997 anyone
using it will be subject to strict regulatory and reporting requirements. This means that
some changes must be made by Spraytek in order to either comply with the regulations
or not be subject to them at all. Some requirements that a cleaning/degreasing process
must meet in order to be suitable for Spraytek are that the parts are cleaned adequately,
the cost of the process is not too great, the parts don't rust and that they are dried during
the process. I have determined several options that Spraytek has that will meet these
requirements and allow them to comply with regulations that do not require an overly
large initial investment.
Other projects that I have spent some time on deal with Aluminum dust disposal,
cleanliness and safety in the lead room and permitting for the recently installed chrome
plating line. The problem with aluminum dust arises during the collection and disposal
of aluminum, steel and stainless steel dusts that are generated during the grinding and
vibrating of sheet metal pieces. The dusts are collected by a wet-type dust collector and
settle to the bottom of a tank of water. The sludge is then removed on a conveyor and
put into 55 gallon drums for disposal. The problem results from a reaction between the
aluminum dust and water that evolves hydrogen gas and heat. These drums had been
getting extremely hot and staying that way for days. Occasionally they had even caught
fire. Also, if the hydrogen gas was able to accumulate there would be an added risk of
explosion. X-L wanted to find a way to dispose of this sludge without these hazards.
The concern in the lead room is over lead and aluminum dusts that accumulate
on the floor and tables during the vibrating of lead and aluminum sheets. This is a
concern because accumulating lead increases the amount of lead that is carried out of
the room on employees, their clothing, or equipment. As it is now, the levels of
airborne lead are well below OSHA standards but if this dust is stirred up into a cloud
the lead could be inhaled and the aluminum could be ignited if an ignition source is
present. The clean up of this dust had been done using a sweeping compound but this
method is not preferred and it made the waste more difficult to dispose of because it is
mixed with the sweeping compound. Therefor, X-L was in need of an effective way to
keep the lead room free of accumulating dust. The method they choose would have to
be able to clean all surfaces, including walls, tabletops and machinery, it must minimize
the risk of re-depositing the lead into the workplace, and it must eliminate the risk of
explosion from the aluminum dust.
The last project I worked on was to gather information on the chrome plating
line including information on the evaporator, what is put into the evaporator, and the
releases/wastes generated by the process. This information was used to fill out the
limited permit application form which will be sent to the Waste Management Division
of the DES. I had hoped that I might be able to work on increasing the efficiency of the
painting operation to reduce waste and also reduce the number of paints used that
contain carcinogens. This could have been done by consolidating the paints that are
similar in color and replacing the paints that contain carcinogens with others that do not.
Unfortunately I did not have tome to get to this and even if I had it would have been
difficult to obtain significant results. The reason for this is that most of the types and
colors of paints that Spraytek used are specified by their customers and are not under
their control.
GOALS AND OBJECTIVES
Degreasing / Paint prep.
- if possible, eliminate the use of TCE
- clean parts effectively without leaving a residue or rusting the parts
- parts must be dry after cleaning
-utilize existing degreasing equipment to save money and facilitate conversion
- comply with CAAA National Emission Standards for Hazardous Air Pollutants
(NESHAP)
- increase worker health and safety
- reduce pollution
Aluminum dust disposal
- dispose of sludge in a way that eliminates hot smoldering sludge as well as the
risk of fire or explosion
Lead Room
- keep room free of lead and aluminum dust (including floors, walls, tabletops
and
equipment)
- minimize the risk of re-entry of lead into the workplace
- eliminate the risk of igniting an aluminum dust cloud
- increase worker health and safety
Chrome Plating Line
- gather required information and fill out documentation to obtain a permit for
the new
process line
APPROACH / METHODOLOGY
The first thing I did when I started at X-L and Spraytek was to familiarize
myself with each operation that was related to my projects and the people
involved with each operation. For the degreasing/paint prep operation this
consisted of determining the types of parts that were being cleaned, the work load
that is put through the degreaser, what contaminants were being cleaned off the
parts, and how the machines were operated. I did this by talking to people at the
facility and obtaining the degreaser manuals and the records of TCE use. My
next step was to learn as much as I could about the NESHAPs for solvent
degreasers. I did this by attending a Teleconference on compliance strategies for
solvent degreasers and reviewing the booklet from this conference along with
some additional information provided by the DES. At this point I was able to
determine what would need to be done in order to comply with the new
regulations if Spraytek decides to continue using TCE. I then contacted several
companies selling degreasing equipment to get information and prices for
emission control devices such as freeboard refrigeration devices ("chillers) and
hoists.
At this point I focused my attention to finding an alternative to cleaning
with TCE. I went to the library to get some general information on aqueous
cleaning and began working with Amanda Heath on the SAGE program (Solvent
Alternatives Guide). The results from SAGE included ratings on the suitability
of different types of cleaners and different types of processes based on Spraytek's
cleaning requirements. Amanda also sent me a list of aqueous cleaners and
alternative solvents and the companies that sold them. Based on the SAGE
results and Spraytek's cleaning needs I determined which of the cleaners might be
suitable and contacted companies to request information on them. Based on the
information provided by these companies I requested samples of the cleaners that
seemed promising and performed some tests. For these tests I used two buckets,
one for a wash tank and the other for a rinse. I used steel, stainless steel and
aluminum pieces that I dirtied with contaminants that were typical at Spraytek.
The wash solution was mixed to the suggested concentration and heated to 140 F.
The dirty metal pieces were put into the wash bucket and agitation of the bath
was begun. After ten minutes in the agitated wash bath the pieces were removed,
rinsed and dried, and the results were recorded. Based on these test results, the
product information and the cost of each cleaner I was able to narrow the list
down to two aqueous alkaline cleaners.
Shortly after I finished testing the cleaners a salesman who was visiting
Spraytek mentioned that there were water based cleaning/phosphating solutions
available that would eliminate the need to use TCE as well as eliminating the
wash priming step. This step uses a wash primer and a catalyst reducer (which
are both very high in VOC content) to apply a coating to the parts so that the
paint will adhere well to the surface. This cleaning/phosphating solution would
apply a coating of iron phosphate that would do the same thing as the wash
primer. Following this conversation I contacted representatives from Oakite and
Hubbard Hall who provided me with some more information. I was able to visit
Rapid Finishing with Art Berner, president of A.J. Associates who represent
Oakite. They have a cleaning/phosphating process at Rapid Finishing that is very
similar to the one that would be used at Spraytek. They provided me with some
input on how the process has worked for them and allowed me to try the system
out on one of Spraytek's parts. I tested this part using only the wash and rinse
steps and skipped the final sealant dip. I did this to see if the sealant was actually
needed for Spraytek because some companies have been able to make the process
work for them without the sealant (the sealant is used to prevent rusting). At first
the results seemed good. The part was clean and you could see a blue coating of
iron phosphate on the part but before we made it back to Spraytek the part started
rusting. I visited Rapid Finishing a second time the following week and tested
the process on a second part, this time using the sealant. The results from this
test were good. The part was clean, the coating was visible and the part didn't
rust. From these two visits I learned that a sealant would definitely be needed for
Spraytek to use this process al well as some things about how the process would
work and what would need to be done to maintain the process.
During this time I had also been contacting companies to get information
about rinse tanks and parts dryers for use in an aqueous cleaning process. I was
also working on determining what alterations would need to be made to the
degreaser if it was to be used with an aqueous cleaner. This included designing
an apparatus that would use compressed air to keep the rinse tank agitated and an
apparatus to spray the parts in the wash tank. This spray apparatus would spray
the parts as they were being lowered into the cleaning tank to increase the
cleaning effectiveness as well as utilize the full space that is available inside the
degreaser tank. Another thing I worked on was determining what Spraytek's
options were for dealing with the waste water if they found that a large volume
was being generated once the system was running.
The first step I took when approaching the lead project was to consult the
lead and aluminum standards to determine what the housekeeping requirements
were. From these I found that it was all right to use a vacuum to clean up these
dusts provided that the vacuum was equipped with a HEPA filter so that even
microscopic lead particles were not returned to the work environment ant that it
was explosion proof so that it would be safe for use with combustible aluminum
dust. The requirement that X-L had was that it could be used to clean all surfaces
including walls, floors, tabletops, machinery and hard to reach areas. At this
point I asked Amanda if she could find some vendors who might offer some
equipment that could do this. From the vendor names she gave me I was able to
find a vacuum that could fulfill X-L's needs.
CHEMICAL USAGE / EQUIPMENT NEEDS
Degreasing / Paint prep.
- Small batch vapor degreaser; solvent-air interface = 8 sq ft
- Large batch vapor degreaser; solvent-air interface = 18 sq ft (not
currently
in use, equipped with an overhead hoist)
- trichloroethylene
- paint booth and spray gun to apply wash primer
- Sherwin Williams wash primer
- wash primer catalyst reducer
RELEASES / WASTES GENERATED
(amounts estimated from 1994 records)
Degreasing / Paint prep.
- TCE 1200 gal/yr
- wash primer
VOC
toluene
xylene
2-propanol
2-methyl-1-propanol
methyl isobutyl ketone
percent
< 5%
< 5%
30%
10%
30%
- catalyst reducer
VOC
percent
2-propanol 50%
methyl ethyl ketone 45%
- 1930 lbs/yr of wash primer and catalyst reducer combined
- 14650 lbs/yr of TCE; 100% volatile
Lead Room
- lead and aluminum dust
- lead shavings and scrap lead ( sold for recycled)
- rags, cardboard etc. that is contaminated with lead
- four 55 gal. drums per yr; a mixture of aluminum, steel and stainless
steel dusts
Chromate Line
- sludge from evaporator; approx. one 55 gal drum per year; EPA waste
code F006
WORK ACCOMPLISHED / PROJECT RESULTS
Lead Room
X-L's goal was to find an effective way to keep the lead room free of lead
and aluminum dusts in order to reduce health risks ad safety hazards. I was able
to find an explosion proof wet/dry vacuum with a HEPA filter that would be able
to handle both the lead and aluminum dusts. It also has all the attachments
needed to clean walls, floors, hard to reach areas and even overhead pipes. The
vacuum is a Nilfisk model and is available in a pneumatic or electric powered
version. The pneumatic powered version costs about $4000 and the electric
version costs about $6000. This is compared to a standard wet/dry vacuum with
a HEPA filter that could handle lead but not aluminum and runs about $800.
The reason for the price difference is that in order for the vacuum to be explosion
proof all of its components must be made out of non-sparking, static conductive
materials and everything including the filters has to be grounded to prevent static
buildup and sparking that could ignite an aluminum dust cloud. X-L basically
had two choices. The first option was to spend the money on the explosion proof
vacuum and continue operating as they were. The second option was to eliminate
all of the aluminum dust that is being generated in the lead room so that they
could use a standard wet/dry vacuum with a HEPA filter to clean the dust. For
the time being X-L has opted for the second choice. This may also have an added
advantage because the dust collected will be all lead instead of a mixture, making
it much easier to recycle. If X-L finds that it is too difficult to keep the lead room
totally free of aluminum dust they will then need to purchase an explosion proof
vacuum. I have provided them with the information on the explosion proof
vacuum in case it is needed down the road.
Aluminum/steel/stainless steel dust disposal
The solution to this problem was straight forward. The first thing that was
tried was to simply let the sludge dry out on a screen before it was put into the
disposal drum. This has eliminated the problem of the drums getting smoldering
hot as well as the risk of them catching fire. X-L plans to continue operating in
this manner. Also, the dust collector requires about 30 gallons per day to operate.
X-L has started using a waste water stream from their tumblers to replenish the
dust collector. This waste water is actually clean enough to go down the sewer
but by operating in this manner they are able to combine two waste streams into
one. Once the sludge is dried it is sent to a company in Louisiana who uses it in
mixing concrete.
Chromating line permit
I have completed the limited permit application form for this process and
given it to Peter Pelletier at X-L. Once the results from a TCLP test for metals
are received this form can be sent along with some other information that I gave
to Peter can be sent to the Waste Management Division at the DES.
Degreasing / Paint prep.
The results of this project are not as cut and dry as the others. There are
several options that are available to Spraytek. In this section each of these
options are explained. I have attempted to explain as clearly as possible what is
required for each option, the advantages and disadvantages of each option, and a
rough estimate of the cost and projected savings of each.
Option 1: Continue using TCE
The use of TCE is not going to be banned but it will be strictly regulated.
It is an option to continue using it, however there are several things that must be
changed about the degreaser and the way it is operated before Dec. 2, 1997.
These changes include equipment modifications, work practices and reporting. I
have already sent in the initial notification form which tells that Spraytek is
affected by the new regulations and explains what the anticipated method of
compliance is. Either of the two machines could be improved for continued use.
Required Work Practices
The new regulations clearly outline what the correct work practices are.
First of all, the operator will no longer be able to lower parts into the machine
manually. This will need to be done by a hoist and the parts will need to be
moved into and out of the degreaser at no more than 11 feet per minute at all
times. If the parts are larger than 50% of the solvent-air interface then the parts
must be lowered at no more than 3 feet per minute. Second, parts that do not fit
completely into the vapor zone will not be allowed to be cleaned in the degreaser.
This means that, if the smaller degreaser continued to be used, long beams that
are longer than 4 ft in any one direction and parts that are longer than 2 ft in any
two directions can not be cleaned in the degreaser. For this reason, as well as
because it is much newer, I would recommend improving the larger degreaser for
continued use if this option is chosen. A complete list of the required work
practices is given in appendix A. Also, any person who will be operating the
degreaser may be subject to an on the spot test by an inspector. A copy of this
test and a more complete description of the regulations can be found in the
booklet on compliance strategies for solvent degreasers that I have given to X-L
and Spraytek along with this report.
Equipment Modifications
There are a few modifications that must be made to the degreasers as well
as control devices that will need to be added to reduce emissions.
small degreaser
1) Install a hoist above the degreaser to lower the parts. Automated hoists
are available but are very expensive and are much more elaborate than anything
Spraytek would need. A standard industrial hoist can be used but it will need to
be re-geared so that it would operate at less than 11 feet per minute. Peter Duke
from Merrimack Handling Equipment can be consulted on this issue.
2) A freeboard refrigeration device ("chiller") will have to be added to the
machine to reduce emissions. This device operates by establishing a cold air
blanket above the vapor zone to prevent vapors from escaping from the
degreaser. This chiller will need to be built into a collar that will extent the
freeboard at least 4 more inches in order to increase the freeboard ratio to 1.0. I
have included a proposal given by Ultra-Kool for such a device with the report
given to X-L.
3) The vent on the rear edge of the degreaser will have to be removed to
reduce drafts that result in increased emissions.
large degreaser
1) The existing hoist above the machine will have to be re-geared in order
to lower the parts at less than 11 feet per minute.
2) A freeboard refrigeration device with a collar to extend the freeboard at
least 4 inches would need to be installed. This is the same as the one that was
proposed by Ultra-Kool for the small degreaser except that it would be larger.
The cost should be fairly close to what was proposed for the small machine.
Record keeping and Reporting Requirements
For the first five years records must be maintained on the operation of
these control devices. Measurements of the hoist speed must be taken and
recorded monthly. The temperature of the air blanket created by the chiller must
be measured and recorded weekly to ensure it is kept below 30% of the solvents
boiling point (for TCE this temperature is 56.7F). If the large degreaser were
used measurements of the air drafts around the degreaser must be taken and
recorded weekly. Records of the annual solvent consumption will also need to be
kept. Additional information about the degreaser will need to be kept on hand as
outlined in the reporting and record keeping section of the booklet on compliance
strategies. There are also several reporting requirements explained in this
section. These include an initial statement of compliance report, annual reports
and exceedance reports.
Cost Analysis
The 1994 TCE consumption was 1220 gallons. At $0.48 per gallon this accounts
for roughly $8000 per year spent on TCE. This amount will most likely increase
as production increases and the price of TCE increases. The cost of installing a
chiller with a freeboard extending collar along with a hoist will be between
$10,000 and $15,000. Ultra-Kool guarantees at least a 40% reduction in solvent
consumption upon installing the chiller. This accounts for a $3200 per year
savings based on 1994 solvent consumption and prices. The estimated pay back
time is 3 to 4 years.
Advantages
- guaranteed clean, dry parts; cleaning power of TCE is excellent
- No new process tanks are required
Disadvantages
- Many new record keeping and reporting requirements
- Does not eliminate health hazards or health risks associated with TCE
- The price of TCE will most likely increase once these regulations are put into
effect
- Risk of added expenses from fines if found in violation of regulations
- If the small degreaser is used a different method will be required for cleaning
large parts
- The additional was priming step will still be needed
- Does not eliminate pollution associated with using TCE
Option 2: Clean Parts with an Aqueous Cleaner
There are differences between aqueous cleaning and vapor degreasing that
require that some changes be made to the current process. It will be possible to
utilize the large degreaser/phosphatizer as an immersion was tank if some
alterations are made to it. These alterations include disconnecting the cooling
water coils and the water separator. An explanation of these alterations along
with a copy of the plans for the degreaser showing where the alterations are
needed is given in Appendix B. Along with the required alterations it would be
advantageous for Spraytek to use some high pressure spray nozzles. This would
greatly increase the cleaning effectiveness of the system. If only an immersion
step was used to clean the parts Spraytek may find that many of the parts are
being rejected because they aren't clean enough. Using high pressure spray along
with an immersion step would cut down on the occurrences of rejects. I have
designed a spray apparatus that could be constructed by people at X-L and added
to the degreaser. This apparatus will spray every inch of the parts as they are
being lowered down into the degreaser. This will also utilize the entire space that
is available inside the degreaser. Since the tank is 10 feet deep it would be
impractical to fill the tank to this depth with the cleaning solution and the tank
walls may not even be able to handle the pressure if the tank was filled this high.
If spray was used then the tank could be filled to a more reasonable depth of 3 to
4 feet. The specifications for this spray apparatus are shown in Appendix C.
Along with these alterations to the degreaser Spraytek will also need to
add a second rinse tank. This tank would be heated so that the parts will dry
themselves when removed. Compressed air may also be needed to blow excess
water off the parts and prevent the drip edge on flat parts. The water in the rinse
tank can be tap water but Spraytek may find that tap water leaves behind residues
upon drying. If this is the case and it is affecting paint adhesion then a rinse with
deionized water will be needed. A suitable rinse tank can be purchased from
Ramco (information and a proposal on this rinse tank have been included with
the report given to Spraytek) or, as was done at Rapid Finishing, X-L could
construct the rinse tank themselves. This tank will need to be equipped with an
overflow and fresh water constantly added to keep the tank clean. It will also
need to be agitated so that the parts are rinsed effectively. This can be done using
compressed air. Information on the requirements of this rinse tank are given in
Appendix C.
Based on the tests I did on the various cleaners, the product information
and the cost of the cleaners I was able to narrow the list down to two alkaline
aqueous cleaners. These are Blue Gold industrial cleaner and Beyond 2002 low
foam spray cleaner (see appendix D). These cleaners would be diluted with tap
water to a concentration of about 5%. The concentrations are maintained by
using a simple titration procedure and then adding more cleaner concentrate to
adjust the pH. This is done until adding more concentrate doesn't adjust the pH,
at which point the bath will need to be disposed of and a fresh bath put into the
tank. The spent solution may or may not be able to be discarded into the sewer
depending on the types and amounts of contaminants that were removed from the
parts.. Spraytek will need to consult with their waste water treatment facility on
this issue.
There are a few other options that Spraytek may want to consider after
running the process for a while. If there is a difficulty in drying the parts
Spraytek may decide to purchase a dryer. A proposal on an affordable dryer has
been included with the report given to Spraytek. Also, if it is found that a large
amount of waste water is being created and causing problems with disposal then
there are a few options to consider. Information on these options is given in
Appendix F.
Advantages
- eliminate health hazards, safety risks and pollution by eliminating the use of
TCE
- avoid reporting and record keeping requirements associated with TCE
- Save money spent on TCE
- eliminate risk of fines if found not in compliance
Disadvantages
- cleaning power is not as strong as TCE
- parts do not dry as easily
- additional rinse tank is required as well as alterations to the degreaser
- possibility of rusting if parts don't dry fast enough
Cost Analysis
- estimated cost of spray apparatus is $1000; including pump, nozzles and
stainless steel piping
- a 55 gallon drum of cleaner concentrate is roughly $500; used at 5% this will
fill the tank twice and should last at least one year
- price of a rinse tank from Ramco is roughly $6000. It would be cheaper if X-L
constructed the tank
1994 TCE consumption
$8000/yr
- 55 gal. drum of concentrate
- $500
- spray apparatus
- $1000
- rinse tank
-$6000
= savings
$500 first year; at least $8000 each following
year
- estimated pay back time is less than one year
Option 3: Clean Parts with an Aqueous Cleaning/Phosphating Solution
Many of the things that are required for this option are the same as what is
required for using an alkaline aqueous cleaner. The required modification to the
degreaser are exactly the same (see Appendix B). It is also recommended to
incorporate the spray apparatus (see Appendix C) for the same reasons as in
option 2. The difference is that this option requires two additional tanks instead
on one. One tank is a rinse tank and the final tank contains a sealant.
This process operates in the following manner. The converted degreaser
will contain the cleaning/phosphating solution. In this tank the parts will be
cleaned and a coating of iron phosphate will be applied to the parts. this coating
ensures that the paint will adhere well to the parts. This would eliminate the
wash priming step the Spraytek now uses to accomplish the same thing. This
wash tank should be heated and the spray apparatus used to enhance the
effectiveness of the cleaning process. The second tank is a rinse tank operated at
room temperature. This tank should effectively stop the reaction that applies the
iron phosphate coating. If too much dragout from the wash tank collects in this
rinse tank then the pH will be too low to effectively stop the reaction. For this
reason the rinse tank must be kept very clean so it must be equipped with an
overflow with fresh tap water being constantly added to the tank. This tank could
be constructed by X-L. An example of a suitable tank is shown in appendix C.
The third tank is a sealant tank that serves to ensure that the reaction has been
completely stopped. It also prevents the parts from rusting which can occur on
the steel parts during humid weather. This tank should be heated so that the parts
dry themselves after being removed. It can also be constructed by X-L and
requires no overflow.
At Rapid Finishing they have a process that is similar to this one. They
obtain their chemicals through Art Berner with A.J. Associates. The products
that Spraytek would want to use are Oakite Cryscoat 747LTS and Cryscoat UltraSeal. These can be obtained through Art Berner as well. Information on these is
available in Appendix E. When talking with Keith at Rapid Finishing he said
that they were very happy with the way the process was working for them and
that they hadn't had any problems at all with paint adhesion.
The techniques used to maintain these tanks are simple titration
procedures as with maintaining alkaline cleaner tanks except that it is more
critical that the concentrations be kept at the desired levels to ensure that the
coating is applied properly. This procedure can be performed in less than five
minutes. Art Berner works closely with Rapid Finishing to maintain their tanks
and would do the same for Spraytek. As with option 2 the tanks will eventually
need to be changed. The waste water considerations are the same as for option 2
and are found in appendix F.
Advantages
- eliminate the health hazards, safety risks and pollution associated with TCE
- eliminate wash priming step which is a contributor to Spraytek's VOC
emissions
- save money spent on wash primer, catalyst reducer and employee wages to
perform wash priming step
- avoid reporting and record keeping requirements associated with TCE
- save money spent on TCE
Disadvantages
- two additional tanks are required along with the modifications made to the
degreaser
Cost Analysis
The capitol cost of this system will depend on what it costs X-L to construct the
two additional tanks. The chemicals would cost about $1000 to fill both the wash
and sealant tanks to the required concentration. Cost to maintain the system will
depend on the work load and the amount of contaminants on the parts.
Savings associated with eliminating use of TCE, wash primer and catalyst
reducer (based on 1994 usage quantities and prices):
TCE
$8000/yr
wash primer and
$3550/yr
catalyst reducer
.
savings
11,550/yr - not including employee wages to perform wash
priming step
POLLUTION PREVENTION BENEFITS
lead room
- reduce the amount of lead that is tracked out of the lead room by increasing the
cleanliness
- improve worker health and safety and reduce insurance liabilities
degreasing / paint prep
- Installing emission controls on the degreaser and continuing to use TCE will
reduce emissions by at least 40%.
- Converting to an aqueous cleaner will eliminate TCE use that totaled 14,500 lbs
in 1994.
- Converting to an aqueous cleaning/phosphating solution will eliminate TCE as
well as wash primer and catalyst reducer which accounted for 1930 lbs of VOC's
released in 1994
- improved worker health and safety
- money saved on TCE, wash primer, catalyst reducer and employee wages
- avoid reporting and record keeping requirements
- avoid fines if found not in compliance
REFERENCES
Clean Air Act Compliance for Solvent Degreasers. The University of Tennessee
Center for Industrial Services and the Tennessee Department of Environment and
Conservation. April 1995