Highlighted_UFC_4_211_02_Air_Compressors.pdf

UFC 4-211-02

1 December 2012

UNIFIED FACILITIES CRITERIA (UFC)

AIRCRAFT CORROSION CONTROL

AND PAINT FACILITIES

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

Provide plumbing in accordance with UFC 3-420-01 and as follows:

Provide one shower for every ten (10) employees (or fraction thereof) of each sex who are required to shower during the same shift. Each rest room must have direct access to appropriate lockers and showers.

Emergency eyewash/safety showers where required must conform to Appendix D of UFC 3-420-01.

Floor Drains in the hangar area, paint mixing rooms and paint equipment cleaning rooms must be connected to the Industrial Waste system or piped to an isolated holding pit for testing to determine proper disposal of effluent

Locate storm-water drains at least 12 in (310 mm) from the hangar access door rails.

3-4.2 Industrial Waste.

Provide a connection to an Industrial Waste Treatment System or to a collection containment tank or pit from all drains in process areas.

Provide for zero discharge from the facility unless the facility will discharge to an existing or new industrial waste treatment facility (IWTF) or to a municipal sewer system. The IWTF must be capable of handling both the type and volume of the chemicals that will be discharged. Disposal into a municipal sewer system requires a minimum pretreatment in compliance with 40 CFR Part 403, or AFI 32-7041.

3-4.3 Control of Hazardous Effluents.

Provide AFFF/Sprinkler discharge collection/retention system when required by environmental regulations for testing and pre-treatment prior to discharge into the appropriate waste stream. For design of containment systems and disposal requirements for AFFF solution, refer to ETL 1110-3-481, Containment and Disposal of Aqueous Film-Forming Foam Solution.

The corrosion control process generates large amounts of water that could potentially hold solid or liquid paint residue or other solvents and wastes. If the local wastewater treatment plant cannot accept the effluent generated from the facility, on-site treatment or containment and off-site disposal is required. Refer to UFC 4-451-10N, Design:

Hazardous Waste Storage, and UFC 4-832-01N, Design: Industrial and Oily Wastewater Control. Design for accidental spill of paint strippers and thinners, paint, cleaning solvents, pretreatment chemicals, fuel or oil. Provide above-grade containment of accidental spills with appropriate sumps for pumping and cleanup of spilled wastes.

Size the containment capacity for the largest possible discharge. Provide a method to prevent the drains from clogging.

3-4.4 Compressed Air.

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Provide low-pressure air for operation of tools and for breathing air in accordance with the following criteria:

Provide low-pressure compressed air at 40 percent to 60 percent humidity and at 125 psig (862 kPa) for shop use. Air should be oil-free to prevent paint contamination. Air outlets supplying tools requiring lubrication should be equipped with an in-line lubricator. Rotary oil-free compressors are recommended since this compressed air may be used as a source for breathing air at lower life cycle costs.

Provide low-pressure compressed air at 20 psig (138 kPa) or higher if required, at 40 percent to 60 percent humidity for breathing air in the hangar bays. The breathing air compressor must minimize moisture content so that the dew point is 10 degrees Fahrenheit (5.56 degrees Celsius) below the ambient temperature. Breathing air must be obtained from the oil-free shop air source through final purifiers in each bay or from a separate breathing air compressor and piping system that meets requirements by OSHA for minimum Grade D air as described in ANSI/CGA G-7.1 Commodity Specification for Air. Breathing air from the oil-free shop air source is preferred because of lower cost.

The air outlets (quick connect fittings) for oil-free shop air, lubricated tool air, and breathing air must be different for each service and must not be compatible with each other.

Typical outlet quantities for each bay are: four breathing and four oil-free shop air and two lubricated tool air. Typically, two oil-free shop air outlets are required per ancillary space. Verify actual requirements for each site.

Locate the intake for breathing air in an uncontaminated area. Air-line respirators approved with a vortex tube will substantially reduce the temperature of the air supplied to the respirator in cases where the supplied air is from a high temperature environment

3-4.5 Process Systems.

The chemicals used in the aircraft corrosion control process can be hazardous to workers, corrosive to the facility infrastructure, and require considerable floor space to store, access, and distribute. The Using Activity must provide a complete list of all chemicals used in the process with relevant MSDS’s to the design team during the planning and design phases to insure that the facility can control the hazards appropriately. The data sheets will also be utilized in the design of the process systems to select compatible materials to contain and distribute the process chemicals used in the aircraft preparation and painting.

3-5 HEATING, VENTILATING & AIR CONDITIONING (HVAC)

General requirements for HVAC design are identified in UFC 1-200-01. Additional design guidelines for LonWorks® based control systems include UFC 3-470-01, Minimize the open cross sectional area in the hangar bay during the design of the hangar structure to reduce the total quantity of airflow while maintaining a safe, efficient working environment.

Airflow recirculation may also be investigated as a means to reduce energy usage while still maintaining worker safety. See Section 3-5.2.7 Consideration of Airflow Recirculation and Section 2-3 HVAC System Planning & Selection.

NOTE: Recirculation of exhaust air or reduced air flow during painting may result in a DeMinimus violation from OSHA. See Appendix D, Fig. D- 2 – OSHA Interpretation regarding the DeMinimus violation.

Ventilation and airflow requirements for chemical de-paint operations are dependent upon the makeup and toxicity of the material being applied to the aircraft for paint removal. The de-paint material manufacturer must be consulted to obtain the applicable MSDSs for the determination of the appropriate ventilation rate.

Filtration must be provided for the Supply Air upstream of the supply fans and in the supply plenum doors. The filters must have a MERV 5 or better rating on the basis of ASHRAE 52.2 Method of Testing General Ventilation Air-Cleaning Devices Used for the Removal Efficiency by Particle Size.

Note: MERV or Minimum Efficiency Reporting Value, is a measurement of air filter efficiency established by ASHRAE. The MERV number ranges from 1 to 16; the higher the MERV number, the higher the efficiency of the air filter at removing particulate matter.

3-5.2.4 Space Static Pressure Controls.

The ventilation system must maintain a slightly negative static pressure of -0.02 to -0.04

in. water gage between the hangar area and the exterior to prevent fugitive hazardous emissions from escaping the hangar envelope and entering the atmosphere. Some studies indicate that a slightly negative pressure in the painting area also provides for more superior painting and reduces turbulent flow. (Refer to System-Level Computational Fluid Dynamics: Advanced CFD Tools to Solve Problems of Operational Conditions, States of Large-Scale Engineered and Natural Systems for additional guidance.) Maintain a slightly higher pressure in the adjacent ancillary and overhead ceiling spaces outside the hangar area to keep the hazardous vapors given off by painting agents from infiltrating into these spaces. Ventilate the space above the hangar bay ceiling to provide a non-hazardous space for light fixtures.

3-5.2.5 Gauges, Safety Interlocks and Alarms.

Install visual gauges, audible alarms, and/or pressure activated devices on filters to ensure that the minimum air velocity or volume is maintained. Interlock the fans and the process air compressors so that the paint spray air compressors cannot operate when the fans are inoperative or below a preset minimum. Breathing air must never have an interlocked shut down. Interlock the fans and the fire protection system so that the fans accomplished in addition to any other mechanical preventative maintenance (belt adjustment/ replacement, filter changes, greased bearings) that is normally performed on the mechanical equipment.

B-5 LESSONS LEARNED

The purpose of this section is to highlight selected lessons learned during the design, construction, and operation of corrosion control facilities that have been previously built.

These lessons can be a good tool for guidance in the design of new and renovated facilities. By not repeating these mistakes, we hope to be able to design better facilities that will meet the needs of the users, state, local, and federal regulatory agencies.

Eliminating the need for modifications to new or renovated facilities could potentially save millions of dollars.

The following are lessons learned from existing Air Force corrosion control facilities.

B-5.1 Dimensions of Booth/Bay.

Ensure that all dimensions of the largest aircraft to utilize the facility are taken into consideration during the design phase of the booth. The measurements must include adequate additional space for maintenance stands and work areas.

B-5.2 Incorporating Fall Protection Control Measures.

If fall hazards cannot be eliminated, fall protection and prevention measures must be incorporated or installed in all corrosion control facilities to ensure the safety of all personnel while working on the aircraft. If fall protection are incorporated into the design phase of the project, it will eliminate the need for added cost in rework to later install the system. Attached safety harnesses will allow for proper complete aircraft paints and eliminate the need to paint portions of aircraft outdoors or in unauthorized hangars. AFOSHSTD 91-100, Aircraft Flight Line – Ground Operations and Activities, paragraph 8.2.5 states that “Whenever it becomes necessary to perform required tasks where a worker can fall 4 feet or more, fall protection will be used.” See AFOSHSTD 91-501, Air Force Consolidated Occupational Safety Standard, for more information on fall protection equipment. EM 385-1-1, Section 5 and Section 21, addresses fall protection requirements.

B-5.3 Proper Sizing of Air Compressors.

Research what size compressor will be needed to accommodate all facility requirements based on all workers using tools simultaneously. It is also important to ensure that the building is wired to accommodate the proper size compressor.

B-5.4 Equipment Designation.

For some services and installations, it may make a difference if special equipment is designated as real property. This designation may effect which parties can accomplish repairs and routine maintenance. It may be beneficial to coordinate equipment

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