HIGH VOLUME/LOW PRESSURE PAINT SPRAY SYSTEM

Revision Date: 8/03
Process Code: Navy/Marines: IND-006-04, IND-005-01, IND-005-02; Air Force: PA01; Army: PNT
Usage List: Navy: High; Marines: High; Army: High; Air Force: High
Alternative For: High Velocity Paint Spray Systems
Compliance Impact: Medium
Applicable EPCRA Targeted Constituents and CAS Numbers: Toluene (CAS: 108-88-3), Xylene (CAS: 1330-20-7), Methyl ethyl ketone (CAS: 78-93-3), Acetone (CAS: 67-64-1), n-Butyl alcohol (CAS: 71-36-3), Lead (CAS: 7439-92-1), Chromium (CAS: 7440-47-3), and Zinc compounds (No CAS)

Overview: A High Volume/Low Pressure (HVLP) paint spray system is an efficient technology for the application of paint to specific workpieces. These systems operate at low pressures, which result in the application of paint at low velocities.

HVLP paint systems atomize paint by delivery a high volume of air at a low pressure [less than 10 pounds per square inch (psi)]. Because the atomized paint particles are delivered at low velocities to the object being painted, less paint is lost as overspray, bounce, and blow back. Typically the transfer efficiency with HVLP paint system is 50 to 65%.

The effect of this technology on pollution prevention concerns the fact that delivering at low velocities results in a higher transfer efficiency, compared to conventional paint spray systems. In conventional spray systems, a stream of liquid paint is met by jets of pressurized air which form the paint into a fine mist. A typical system employs 100 psi of constant air pressure in a volume of approximately 25 cubic feet per minute (cfm). The atomized paint particles travel at high velocities and tend to bounce off the object being painted rather than adhering to the surface. In addition, the expanding high pressure air (above 100 psi) passing through the small face cap openings causes turbulent flow of the paint stream following air currents within the paint booth. The amount of paint that bypasses the workpiece (overspray) is relatively high for air pressure atomized spray painting. Transfer efficiencies of 25 to 30% are associated with conventional spray systems.

There are three other types of high transfer efficiency paint guns: airless (also called pressure atomized), pressure atomized air-assisted, and electrostatic. Electrostatic paint spray systems are discussed in a separate Pollution Prevention Opportunity Data Sheet, Electrostatic Paint Spray System. The other two systems are described below.

Airless spray painting systems atomize paint by forcing it through a small tip orifice at high fluid pressures (1,500 to 3,000 psi). Transfer efficiencies with airless spray painting are lower than HVLP systems, typically 20 to 40%. Large areas can be painted quickly by pressure atomized paint systems. This technology is, however, inappropriate for fine finishing work, because a large quantity of paint is delivered with particles that are less finely divided.

Pressure-atomized, air-assisted systems combine the features of the air atomized (conventional) and airless systems. An airless fluid spray nozzle is used to atomize the coating into a fan pattern at high pressures (400 to 800 psi). A second, low-pressure air stream (10 to 30 psi) is injected after the nozzle to improve atomization and the spray pattern. This system is reported to provide the fine control of air-atomized spray guns and the improved transfer efficiencies of airless systems. Transfer efficiencies for pressure-atomized, air-assisted systems are comparable to HVLP systems. The airless systems generate significant waste during clean-up and material changes, as compared to the HVLP system.


Compliance Benefit: The higher transfer efficiency achieved by the HVLP paint spray system reduces the total volume of paint that is used, which in turn results in the following compliance benefits:
  • Reduces emissions of volatile organic compounds (VOCs) used as solvents in paints that are associated with formation of smog and are typically regulated by federal and state agencies as well as local air pollution control districts;
  • Reduces emissions of hazardous air pollutants (HAPs) used as solvents in paints that are most typically associated with increased cancer risk and which are regulated under federal, state and local regulations including the National Emission Standards for Hazardous Air Pollutants (NESHAP) program (40 CFR 63);
  • Reduces hazardous materials usage as required of federal facilities by Executive Order (EO) 13148, Greening the Government Through Leadership in Environmental Management.
  • Reduces emissions of substances that may result in reduced reporting requirements under the toxic release inventory (TRI), Tier I/Tier II, and other SARA Title III reporting requirements (40 CFR 300, 355, 370, and 372) as well as EO 13148; and
  • Reduces some occupational exposures that are regulated under 29 CFR 1910.120.

Specific compliance benefits include: 1) reduced recordkeeping and reporting requirements under the Title V permitting program, the NESHAP Program, and under SARA programs; and 2) reduced permit fees.

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.


Materials Compatibility: HVLP paint spray systems can be used in a wide variety of painting applications. The finer atomization of HVLP systems produce smoother surface finishes. There are many paint gun models, with a variety of tip sizes to accommodate most coatings, including solvent-based paints, water based coatings, fine finish metallic coatings, high-solids polyurethane, contact adhesives, varnish, top coats, lacquer, enamel primer, latex primer, epoxy, and vinyl fluids. The manufacturers guidance should be followed in all maintenance and operating aspects, particularly when spraying high solids paints. Clogging problems can hamper painting operations if the technician is not familiar with the equipment or the application techniques required. The efficiency of this system is reduced if painting is in exposed areas.


Safety and Health: Proper design, operation, and maintenance of the equipment is required for its safe use. The spray booth must be well ventilated. The coating characteristics and application procedures (such as surface preparation, spraying and clean up) present additional health concerns. The inhalation of lead or zinc can irritate the respiratory tract and may even result in instances of poisoning. Some lead compounds are even known to be carcinogenic. Solvent-based paints can irritate the lungs and mucous membranes. Prolonged exposure can affect respiration and the central nervous system. Proper personal protective equipment (PPE) should be worn.

Consult your local industrial health specialist, your local health and safety personnel, and the appropriate MSDS prior to implementing any of these technologies.


Benefits:
  • Higher transfer efficiencies result in significant reductions in both paint usage and waste generation.
  • Less maintenance is required for pollution control equipment serving the painting area.
  • Paint solvent waste and emissions can be further minimized by utilizing a paint gun cleaning station and solvent recovery system. The USAF has authorized paint gun cleaning stations for use under Table of Allowance (TA) 480.


Disadvantages:
  • HVLP systems are sensitive to changes in temperature, pressure and air flow rate. The operator must monitor these conditions to ensure that proper transfer efficiencies are maintained.
  • Solvent-based paints (epoxy, lacquer, polyurethane, and oil-based enamels) will require a solvent to adequately clean the spray guns.


Economic Analysis: Costs will vary depending upon specific applications, painting/coating type, paint volume, workpiece specifications, and technique. Generally, HVLP paint spray system equipment costs approximately $1,000 for a gun, hose, and paint pot. Airless or air-assisted airless paint spray systems range from $2,000 to $3,500. Installation costs will also vary, depending upon location.

Assumptions:

  • Gallons of paint applied to surface per year: 5,000 gals.
  • Gallons of paint purchased per year with HVLP system: 10,000 gals.
  • Gallons of paint purchased per year with high velocity spray system: 20,000 gals.
  • Paint procurement cost: $50/gal. (Most paints used by the Air Force are two component epoxies or polyurethanes coatings that cost around $100 for a two gallon kit.)
  • Transfer efficiency of HVLP gun: 50%.
  • Transfer efficiency of high velocity spray system: 25%.
  • Labor requirements: The only significant difference in labor between these systems is the maintenance requirements, as there is no difference in painting times.
  • Labor for High Velocity Spray Systems: 400 hrs.
  • Labor savings for HVLP: 10%.
  • Labor rate: $45/hr.
  • Waste paint collected using dry filter system.
  • Dry filter replacement rate: 1.25 dry filters/hr.
  • Dry filter disposal cost: $1/filter.

Annual Operating Cost Comparison for HVLP Spray Systems and High Velocity Spray Systems

  HVLP Spray Systems High Velocity Spray Systems
Operational Costs:    
Labor: $16,200 $18,000
Paint: $500,000 $1,000,000
Waste Disposal: $450 $500
Total Costs: $516,650 $1,018,500
Total Income: $0 $0
Annual Benefit: -$516,650 -$1,018,500

Economic Analysis Summary:

  • Annual Savings for HVLP Spray Systems: $501,850
  • Capital Cost for Diversion Equipment/Process: $1,000
  • Payback Period for Investment in Equipment/Process: Immediate

Click Here to view an Active Spreadsheet for this Economic Analysis and Enter Your Own Values. To return from the Active Spreadsheet, click the Back arrow in the Tool Bar.


NSN/MSDS:
Product NSN Unit Size Cost MSDS*
HVLP Gun 4940-01-315-8352 ea. $364.76  
HVLP Gun 4940-01-345-2132 ea. $303.00  
Paint Outfit 4940-01-316-2146 ea. (2 gal.) $1,303.98  
Paint Outfit 4940-00-255-8683 ea. (5 gal.) $2,791.00  

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


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

The HVLP system is the preferred paint system by the Air Force in T.O.1-1-8 for general paint applications. It is authorized in Table of Allowance 480, but authority resides at the local level.


Points of Contact: For more information

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

US Air Force Table of Allowance (TA) 480 should be used by Air Force personnel for National Stock Number (NSN), sources of supply and costs.

Fluid Air Products (Government Distributor)
12834 Gravois Road
St. Louis, MO 63127
Phone: (314) 729-7000 or (800) 365-7565
FAX: (314) 729-7099
Contact: Mr. Bob Hunt
E-mail: bhunt@fluidair.com

ITW Industrial Finishing
195 International Blvd.
Glendale Heights, IL 60139
Phone: (630) 237-5000
FAX: (630) 237-5003 or (630) 237-5011
Customer Service FAX: (877) 790-6965
Sales & Marketing FAX: (630) 237-5012
Technical Support FAX: (888) 246-5732


Related Links: Do You Use Conventional Paint Spray Guns? - Navy Environmental Quality Initiative (EQI)

High Volume Low Pressure (HVLP) Paint Spray Gun - P2 Equipment Program


Sources: The DeVilbiss Co.
Mr. Vern Novstrup, NFESC, November 1999.


Supplemental: Picture of High Volume Low Pressure (HVLP) Paint Spray Gun - P2 Equipment Program
Picture of High Volume Low Pressure (HVLP) Paint Spray Gun - P2 Equipment Program