1. INTRODUCTION.

The U.S. Department of Transportation, Federal Aviation Regulations (FAR), 14 CFR 121.308(b) requires that, "After April 29, 1987, no person may operate a passenger carrying transport category airplane unless each lavatory in the airplane is equipped with a built-in fire extinguisher for each disposal receptacle for towels, paper, or waste located within the lavatory. The fire extinguisher must be designed to discharge automatically into each disposal receptacle upon occurrence of a fire in the receptacle."

The disposal receptacles are designed to comply with the requirements contained in FAR 14 CFR 25.853 (f) which states, "Each receptacle used for the disposal of flammable waste material must be fully enclosed, constructed of at least fire resistance materials, and must contain fires likely to occur in it under normal use. The ability of the receptacle to contain those fires under all probable conditions of wear, misalignment, and ventilation, expected in service must be demonstrated by test." FAA Advisory Circular 25-17, "Transport Airplane Cabin Interiors Crashworthiness Handbook" provides an acceptable method to show compliance with this rule.

Currently, although not required by airworthiness regulations, the typical aircraft lavatory disposal receptacle fire extinguisher uses Halon 1301. For all practical purposes, the production of halons ceased, as of 1 January 1994, under the provisions of the Montreal Protocol, due to their identification as an ozone destroying compound. As a result, a search for alternative agents was conducted.

2. SCOPE.

To establish the minimum performance standards (MPS) that an agent must meet and which provides an equivalent level of safety to that of Halon, the performance of an agent is measured against a standard test method. This document establishes the fire load, trash disposal receptacle test article, test procedures, and pass/fail criteria for built-in extinguishers for lavatory disposal receptacles.

TOP OF PAGE

3. AGENT SELECTION GUIDANCE.

3.1 ENVIRONMENTAL.

 The primary environmental characteristics to be considered in assessing a new agent are Ozone Depletion Potential (ODP), Global Warming Potential (GWP), and Atmospheric Lifetime. The agent selected should have environmental characteristics in harmony with international laws and agreements, as well as applicable local laws. This MPS sets out the means of assessing the technical performance of potential alternatives, but in selecting a new agent it should be borne in mind that an agent which does not have a zero or near zero ODP and the lowest practical GWP and Atmospheric Lifetime may have problems of international availability and commercial longevity.

3.2 TOXICOLOGY.

The toxicological acceptability of an agent is dependent on its use pattern. As a general rule, the agent must not pose an unacceptable health hazard for workers during installation and maintenance of the extinguishing system. In areas where passengers or workers are present or where leakage could cause the agent to enter the passenger compartment, at no time should the agent concentration present an unacceptable health hazard. Following release during fire extinguishment, the cumulative toxicological effect of the agent, its pyrolytic breakdown products, and the by-products of combustion must not pose an unacceptable health hazard.

4. REQUIREMENTS.

4.1 ENVIRONMENT.

The replacement agent must be approved under the Environmental Protection Agency (EPA) Clean Air Act, Significant New Alternatives Policy (SNAP) program, or other international governmental approving program. Approved agents on the SNAP or other international list must not exceed the established criteria for Ozone Depletion Potential (ODP) and toxicity.

4.2 TOXICOLOGY.

The quantity of agent, when discharged into the protected trash receptacle volume, shall not exceed the NOAEL in the occupiable space within the lavatory. (See appendix A.)

TOP OF PAGE

4.3 FIRE PROTECTION.

The fire extinguisher must successfully extinguish a test fire contained in the test receptacle after automatically discharging into the trash receptacle test article.

Additional testing may be required to substantiate agent/system effectiveness in trash receptacles larger than the 1.333 cu ft volume test article. If an extinguishing system is to be used on receptacles with internal volume larger than 1.333 cu ft, it is the responsibility of the manufacturer to demonstrate the effectiveness of a particular agent amount.

4.4 FIRE THREAT.

The fire threat that must be extinguished is a trash receptacle test article (ref. Section 5.2) filled with crumpled paper towels. The specific requirements for the fire load are contained in Section 5.3

4.5 ACCEPTANCE CRITERIA.

Each lavatory trash receptacle automatic discharge extinguisher must meet the following criteria:

• Five separate extinguisher tests must be performed and each must extinguish the test fire.
• Extinguisher discharge performance must meet the following:
  • The nozzle must activate when the temperature in the test receptacle reaches 175^oF + 5^oF, as measured in Section 5.2.3.2.
  • The extinguisher must activate within 60 seconds of reaching the above activation temperature.
  • The discharge duration must not exceed 15 seconds.
• The test fire must be extinguished and must not re-ignite or flare-up after the access panel to the test receptacle has been opened.
• An extinguisher that meets the requirements for use in trash receptacles up to 1.333 cu ft is acceptable for use in a smaller receptacle, with a similar installation, without additional testing.

5.0 TEST REQUIREMENTS.

5.1 TEST CONDITIONS.

Each test must be performed under the following conditions:

• The ambient temperature must be 80^oF + 20^oF.
• The fire load materials described in Section 5.3 must be conditioned to 70^oF + 5^oF and a maximum of 55% relative humidity until moisture equilibrium is reached for 24 hours. The test must be initiated within 30 minutes of removal of fire load materials from the conditioning chamber if the atmospheric conditions within the test area are different.
• Agent Temperature. Extinguishing systems which utilize a remote agent bottle typically mounted external to the trash receptacle with a protruding discharge tube must maintain an agent temperature of 30^oF or less at the time the agent is discharged (i.e., time of eutectic release). Extinguishing systems which are typically mounted internal to the trash receptacle must maintain a 30^oF agent temperature at the start of the test (i.e., ignition of the fire load).

Examples of maintaining proper agent discharge temperature:

• Example 1. The agent may be kept in a separate cold chamber during the test, ensuring that the temperature will be at or below 30^oF. The cold chamber should be as close to the discharge point of the test article as possible, to allow for the shortest possible transfer plumbing.
• Example 2. Overcooling of the agent may be used when an accurate estimate of the elapsed time can be determined for the eutectic device to open (i.e., the temperature at the top of the test article will reach 175^oF) after initiation of the ignitor. This would allow the tester to back calculate the maximum amount of time available to ensure that the agent is at or below 30^oF, once it is removed from the cold chamber.

TOP OF PAGE

5.2 TEST APPARATUS.

The test standard trash receptacle and extinguisher bottle installation is described below:

5.2.1 Trash Receptacle test Article.

The test receptacle must be constructed of either aluminum or steel of 0.125 inch thickness (nominal). The test receptacle for trash containers up to 1.333 cubic feet (.038 m³) volume is shown in Figure D-1. All receptacle dimensions are internal measurements.

The front of the test receptacle must contain a clear access panel constructed of fire resistant polycarbonate or glass for visual observation. The access panel must be 9.5 + 0.5 inch (24.13 cm) wide by 8.5 + 0.5 inch (21.59 cm) high with the lower edge of the panel positioned 6 + 0.5 inch (15.24 cm) from the bottom surface.

A 2-inch (5.08 cm)-diameter hole must be centered 2 inches up the side of the test receptacle for igniter insertion and must be sealed after insertion of the igniter.

The front and back face of the test receptacle must have six 1-inch (2.54 cm)-diameter holes (12 holes total) equally spaced for ventilation which are equipped with a mechanism for quick opening or closing.

A waste flap opening must be provided at the top of the test receptacle. The opening must be 6.2 inches (15.75 cm) by 6.2 (15.75 cm). A plate which is no more than 0.5 inch (1.27 cm) larger than the opening must be mounted 0.5 inch (1.27 cm) above the opening.

The agent discharge tube (used on systems that are externally mounted) must be centered in the top of the test receptacle, pointing straight down and must protrude into the cabinet 1 inch from the upper surface. A hole in the cabinet shall be provided to allow insertion of the discharge tube, which must fit snugly in the hole. Heat resistant tape can be used on the outer surface of the cabinet to facilitate an airtight seal.

5.2.2 Ignition Source.

A standard electrical resistance igniter must be used. The igniter shall consist of a nichrome wire (nominal 0.025 inch diameter) with 15 loops of 0.25 inch diameter. The length of the ignitor (loop section) must be 1.25 + 0.125 inch. To ensure consistent test commencement, the voltage through the igniter shall be adjusted to provide 1650 +50^oF at the center point. The temperature at the center point should be calibrated as follows:

• Mount a thermocouple, as described in Section 5.2.3, in the center of a vertically positioned ignitor device, making certain that the wires do not come in contact with the igniter, as shown in Figure D-2. Ensure that the thermocouple reading device is functioning properly and protect from drafts.
• Energize igniter and simultaneously start the timing device. Measure temperature at 30, 60, and 90 seconds.
• Repeat 4 times for a total of 5 tests, using a new igniter each time.

TOP OF PAGE

5.2.3 Thermocouples.

Three thermocouples are to be used for testing and must be type K grounded with a nominal 30 American Wire Gauge (AWG) size conductor.

• One thermocouple must be installed on the fire extinguisher to measure surface temperature. To obtain the most accurate reading of the agent temperature, it is recommended that the thermocouple be placed over a non-painted area on the agent vessel and covered using adhesive tape. Lightly sand the painted exterior of the agent vessel if necessary.
• One thermocouple must be installed at the centerline of the test receptacle, as defined in Figure D-1.
• One thermocouple must be placed to measure ambient temperature. 

5.2.4 Instrumentation.

 A data acquisition system or other suitable instrument with an appropriate range must be used to measure and record the output of the thermocouples.

5.2.5 Timing Device.

A stopwatch or other device must be used to measure the time of ignition energizing, smoke generation, open flaming, agent discharge, and extinguishment.

5.3 TEST FIRE LOAD.

The fire load shall consist of crumpled two-ply paper hand towels having a total weight of 815 + 5g.

5.3.1 Paper Towel Specification.

Type: Bleached, C-Fold Deep Embossed handifold towels
External dimensions: 10.25 by 13.25 inches
Weight: 4.5 + 0.1 g per towel
Tensile Strength Dry (grams/inch): 707
Tensile Strength Dry (Kg/15mm): 0.42
Tensile Strength Wet (grams/inch): 189
Tensile Strength Wet (Kg/15mm): 0.11
Absorbency (sec/0.1 ml): 30

TOP OF PAGE

Note: all Tensile strength test results derived from average of both directions

Towels manufactured by:  

Fort Howard Corporation 1919 South Broadway (54304) P.O. Box 19130 Green Bay, WI 54307

Telephone: 1-800-558-7325 Fax: 1-800-635-6906 part number 244-00

Towels distributed by:
W.W. Grainger Inc.
(713) 748-8280
part number 2U215

5.3.2 Paper Crumpling Specification.

Prior to loading the paper towels into the test receptacle, they must be opened and crumpled to simulate used hand towels. This can be accomplished by performing a free fill density procedure in which 340 + 10 paper towels are crumpled to fill an 18- x 18- x 18-inch container to the top level to ensure similarity of crumpling between the various testing facilities. This procedure may require several attempts in order to achieve the proper crumpling tightness.

5.4 TEST BOOTH OR CHAMBER.

The trash receptacle test article should be located in a booth or room containing adequate ventilation capabilities. The maximum air velocity directly adjacent to the test receptacle should not exceed 50 feet per minute.

5.5 TEST PROCEDURE.

• Condition the fire load.
• Weigh the extinguisher and record the value.
• Set up data acquisition system.
• In the test receptacle, install and clamp the igniter 1 inch above the ventilation holes at the approximate centerline of the receptacle, as shown in Figure D-1. A clipping device or other nonintrusive means may be used to prevent the ignition source from skewing left or right when the paper is being loaded into the receptacle.
• Installation of fire load. Remove the observation window and begin loading the crumpled hand towels. Ensure that the entire bottom of the test receptacle is fully covered with a layer of precrumpled towels (also pack one or two precrumpled hand towels under the ignitor to prevent damage during subsequent loading). When approximately one-half of the paper is loaded, reinstall the observation window and finish loading the remainder of 815 + 5 g of crumpled towels into the receptacle through the bin flap. If there is difficulty in fitting the entire 815g of crumpled towels into the test receptacle, it can be shaken lightly to provide adequate space. When all materials are loaded, the edges of the observation window can be sealed with duct tape to prevent air infiltration or agent release. The test must be initiated within 30 minutes of removal of the fire load materials from the conditioning chamber if the atmospheric conditions within the test area or booth are different.
• Mount the conditioned fire extinguisher to the test receptacle per the manufacturer's installation drawing, ensuring that the agent temperature will be at or below 30^oF at the time of discharge (externally mounted type) as described in section 5.1.
• Record initial ambient, extinguisher surface, and test receptacle temperatures.
• Start the data acquisition system.
• Energize the igniter (time =0) and begin to record the times to relevant events as described below.
• Upon extinguisher discharge, remove power from the igniter, immediately close all ventilation holes in the test receptacle, and record the time of discharge. (It is critical that the ventilation holes be closed immediately upon agent discharge to prevent the agent from escaping). If the extinguisher does not discharge within 5 minutes of the igniter energizing, the test should be aborted and considered a non-test.
• If after 5 minutes from the conclusion of the agent discharge, the temperature and visual observations indicate that combustion has ceased, open and secure the access panel.
• If after a further 2 minutes reignition does not occur, empty the compartment and spread the waste into a single layer, observe and note any residual smoldering. Record the extent of fire load consumption, presence or lack of smoldering, etc. If residual smoldering is present, the test is a failure.
• If re-ignition occurs, the test is a failure. Extinguish the fire using water or other environmentally friendly method.
• Weigh the discharged extinguisher to determine and record weight of agent discharged.

5.6 TEST REPORT.

The test report must include the following:

• A complete description of the test receptacle and the fire extinguisher, including photographs, if appropriate.
• Details of the test results should include the temperature of the extinguisher surface, temperature of the receptacle, and the times from ignition energizing to generation of smoke, open flaming, agent discharge, and end of test.

Addtional Information	TOP OF PAGE

For further information contact Tim Marker at Tim_Marker@admin.tc.faa.gov

LAST UPDATED 7/26/99