Currently, WR-ALC at Robins AFB uses a medium pressure water system (12,000 - 15,000 psi). The system is used for coating removal on the C-5, C-130, and F-15 aircraft and also some off-aircraft components. The system is used with either a non-hazardous air pollutant chemical remover, sodium bicarbonate blast media, or by itself depending on the coating being removed.

• Elimination or reduction of volatile organic compounds (VOCs) used as strippers, which are associated with the formation of smog typically regulated by federal and state agencies as well as local air pollution control districts.
• Elimination or reduction of hazardous air pollutants (HAPs) in strippers which are regulated by federal, state, and local regulations including the National Emissions Standards for Hazardous Air Pollutants (NESHAPs) (40 CFR 63).
• Elimination or reduction of SARA Title III reporting (40 CFR 300, 355, 370, and 372).
• Reduced volumes of organic wastes, which must be managed as hazardous waste under 40 CFR 260 and related sections.
• Reduced potential for release of hazardous substances in reportable quantities (40 CFR 110 and 302).
• Reduced occupational exposures, which are regulated under 29 CFR 1910.
• Reduced hazardous materials usage as required of federal facilities by Executive Order (EO) 13148, Greening the Government Through Leadership in Environmental Management.
• Decreased water use as required under EO 13123, Greening the Government Through Efficient Energy Management.

Compliance benefits include: 1) reduced recordkeeping and reporting requirements under the Clean Air Act Title V Operating Permits Program, NESHAPs Program, and SARA programs, 2) reduced administrative burden associated with hazardous waste (i.e., tracking, plans, reports, training), and 3) reduced administrative burden associated with OSHA (i.e., training and recordkeeping).

The compliance benefits listed here are only meant to be used as general guidelines and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g., the amount of workload involved.

Consult your local industrial health specialist, your local health and safety personnel, and the appropriate MSDS prior to implementing this technology.

• Reduces hazardous waste by 90%.
  
• May be adjusted to selectively remove individual coating-layers.
  
• Pre-washing and masking is not needed in most applications.
  
• No size limitations for parts being stripped.
  
• Process water reclamation units capture removed paint and recirculate water.
  
• Lowers implementation cost by utilizing simple robust equipment.
  
• Reduces the process material costs significantly.
  
• Reduces labor hours for the stripping process by 50%.
  
• Does not generates any dust or airborne contaminants.
  
• Requires no cleanup after stripping
  
• Specific additives will control flash rusting and give long term protection.

• High capital costs.
  
• May not remove corrosion.
  
• The characteristics of the coatings to be removed may impact personal protection and waste collection/disposal considerations.
  
• Coating debris sludge is a potential hazardous waste.
  
• Wastewater disposal requirements depend on the toxicity of the coating being removed and wastewater plants' requirements.
  
• Workers must be protected from direct impingement of the water jet.
  
• Operator training is required.
  
• Water can penetrate and/or damage joints, seals, and bonded areas.
  
• Additives to the water may have an adverse effect (i.e., flash rusting) on the surfaces being cleaned.
  
• Stripping rate varies with the type of paint, coating condition and coating thickness.
• This technique is not appropriate for composite or honeycomb thin skinned materials.
  
• The medium pressure water stripping process works well as a supplement to chemical paint stripping, but is not recommended as a stand alone paint removal process for complete aircraft stripping. It has many successful applications as a part/component stripping process. Medium pressure water without abrasive additives, such as sodium bicarbonate, does not always remove paint completely. High-pressure water is not a technology that has proven effective for off-aircraft component paint stripping. Capital investment for high pressure water paint stripping is cost prohibitive.

Assumptions:

• 3 aircraft will be de-painted per month.
• External paint area of each aircraft: 937.8 ft².
• Strip rate for one aircraft: 2 ft²/min for Water Process, 0.22 ft²/min for Chemical Process.
• Labor rate: $30/hr.
• Electricity: $0.08/kw-hr.
• Paint and solvent sludge disposal cost: $4/gal.
• Dry paint waste disposal cost: $2/lb.

Water Process

• Total labor requirements for one aircraft: 7.8 hr/aircraft.
• Material costs: $445/aircraft.
• System electrical requirements: 907 kw-hr/aircraft (see attached note JLR).
• System maintenance cost: $311/aircraft.
• Dry paint waste residue: 30 lb/aircraft.

Chemical Process

• Total labor requirements for one aircraft: 71 hr/aircraft.
• Chemical procurement cost: $10/gal.
• Chemical consumption for a 937.8 ft² aircraft: 35 gallons/aircraft or $350/aircraft.
• Paint and solvent waste: 87 gal/aircraft.

Table 1. Annual Operating Cost Comparison for High Pressure Water Paint Stripping and Chemical Paint Stripping

	Water Stripping	Chemical Stripping
Operational Costs:
Labor:	$8,400	$76,700
Material	$16,000	$12,600
Energy	$2,600	$0
Waste Disposal	$2,200	$12,528
System Maintenance:	$11,200	$0
Total Operational Costs:	$38,200	$101,828
Total Recovered Income:	$0	$0
Net Annual Benefit/Cost:	-$38,200	-$101,828

Economic Analysis Summary:

• Annual Savings for Systems for Water Stripping: $63,628
  
• Capital Cost for Systems for Diversion Equipment/Process: $1,175,000
  
• Payback Period for Investment in Equipment/Process: <19 years

*There are multiple MSDSs for most NSNs. The MSDS (if shown above) is only meant to serve as an example. To return from the MSDS, click on the Back arrow on the Tool Bar.

Appropriate authority for making process changes should always be sought and obtained prior to procuring or implementing any of the technologies identified herein.

Medium pressure water paint removal is an approved process in T.O.1-1-8. However, use of this process requires approval by the engineering authority of the specific Weapon System manager and Equipment Item Manager. High-pressure water paint removal systems are not recommended by the Air Force corrosion Program Office, and technical guidance for the process is not provided.

For Air Force applications, high and medium pressure water paint stripping must not be used on any aircraft or weapon systems without the knowledge and approval of the appropriate system manager, office(s) having engineering authority on the specific airframe(s) and the Air Force Corrosion Program Office.

This is not meant to be a complete list, as there may be other suppliers of this type of equipment.

Carolina Equipment & Supply Company
7251 Cross County Rd.
N. Charleston, SC 29418
Phone: (800) 394-4987 or (803) 760-3000
FAX: (803) 760-3500
Contact: Mr. Chris Fulmer
Service: Medium pressure water systems, Aqua Miser^®
URL: http://www.blastandpaint.com

O'Connell Jetting Systems
Mr. Mike Richardson
3195 "H" Park Road
Benicia, CA   94510
Phone: (800) 320-4848 or (707) 747-4848
FAX: (707) 747-6372

NLB Corporation
29830-T Beck Road
Wixom, MI   48393 2824
Phone: (800) 394-4587 or (248) 624-5555
FAX: (248) 624-0908

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High Pressure Water Jet System - P2 Equipment Program