PPE test methods

The TECP suit pressure test is used to evaluate whether a gas-tight totally-encapsulating chemical protective suit can hold a fixed positive pressure and thus demonstrate gas-tight integrity. This appendix describes a non-mandatory test practice for checking leaks and pressure retention; note that the appendix is guidance while 1926.65(g) makes Level A and B PPE mandatory in certain circumstances.

The minimum pre-test expansion pressure (A) is three inches water gauge and the minimum suit test pressure (B) is two inches water gauge. These minimums appear in the test procedure and the manufacturer may specify higher pressures; see 1926.65AppA for the exact requirements.

Inflate to the test pressure (B) and monitor for three minutes; the ending pressure (C) must be at least 80% of the test pressure (B), so the pressure drop (B−C) may not exceed 20% of B. If the drop is more than 20% during the three-minute interval, the suit fails and must be removed from service per 1926.65AppA.

If the suit fails, inflate the suit to the pre-test expansion pressure (A) and brush or wipe the exterior (including seams, closures, lens gaskets, glove-to-sleeve joints, etc.) with a mild soap-and-water solution and observe for soap bubbles, which indicate leaks. Repair identified leaks and retest as specified in 1926.65AppA.

The test apparatus must include a pressure measurement device with a sensitivity of at least 1/4 inch water gauge. The source of the test apparatus and gauge sensitivity must be recorded in the test report as required by 1926.65AppA.

You must record a unique ID (brand, purchase date, material, special fit features), the actual values for pressures (A), (B), and (C) with observation times, whether the suit passed or failed (C < 80% of B indicates failure), the source of the test apparatus, and the pressure gauge sensitivity. Retest data and identified leak locations should also be recorded as outlined in 1926.65AppA.

The test allows visual inspection and test apparatus attachment; if a component is removed for the test it must be replaced and a second test conducted with another component removed so the entire ensemble is tested. The procedure and handling of removable components are described in 1926.65AppA.

Care must be taken to provide appropriate pressure safety devices for the compressed air source and to test the leak-tightness of tubing and test apparatus before and after each test. Also inspect and secure suits before returning them to service and ensure suits are dry before storage, as stated in 1926.65AppA.

The pressure test evaluates gas-tight integrity (leakage) of the suit but does not determine resistance of suit materials to permeation, penetration, or chemical degradation; those characteristics require separate material tests often conducted by manufacturers (e.g., ASTM methods). See 1926.65AppA for this limitation.

The qualitative ammonia intrusion test is a semi-qualitative method to detect inward leakage of ammonia vapor into a gas-tight TECP suit without modifying the suit, providing a realistic test of the whole ensemble's integrity. The appendix clarifies this test does not assess permeation or material resistance; see 1926.65AppA.

The test room concentration should be brought to between 1,000 and 1,200 parts per million (ppm) ammonia before starting the exercise protocol; the suited individual's interior concentration is measured after the protocol to calculate the intrusion coefficient as described in 1926.65AppA.

Only persons wearing a positive-pressure self-contained breathing apparatus (SCBA) or a positive-pressure supplied-air respirator (SAR) may be inside the chamber; the stand-by person must also have such respiratory protection available. This safety requirement and the ammonia hazards are specified in 1926.65AppA.

Required supplies include high-range (0.5–10 vol%) and low-range (5–700 ppm) ammonia detector tubes with a sampling pump, a bromophenol blue indicator strip sensitive to 5–10 ppm ammonia (or equivalent), and optionally more sensitive detectors for interior suit measurement. These are listed in the appendix under required supplies in 1926.65AppA.

The intrusion coefficient is the level of protection provided by the TECP suit and is calculated by dividing the test room challenge-agent concentration (average) by the concentration found inside the suit. Larger intrusion coefficients indicate greater protection. The appendix defines this under the qualitative test section in 1926.65AppA.

A stand-by person must observe the suited individual throughout the test, assist with donning and doffing, and measure the suit interior concentration after the test; they must also be available with appropriate positive-pressure respiratory protection to enter the chamber if needed, as required in 1926.65AppA.

Concentrated aqueous ammonium hydroxide (58% by weight) is corrosive and volatile; reviewers must consult the SDS and only allow personnel wearing positive-pressure SCBA or SAR in the test chamber. Medical screening for respirator use and allergy checks to ammonia are required; these safety precautions are in 1926.65AppA.

Measure the test area to the nearest foot and calculate its volume in cubic feet; the appendix requires this step (6.1.1) so you can determine how much concentrated ammonia solution to evaporate to reach the target concentration, as described in 1926.65AppA.

Yes — employers must assess workplace hazards and select appropriate PPE before use; OSHA requires a hazard assessment and written certification where PPE is required in general (see guidance in the March 28, 2024 Letter of Interpretation on PPE hazard assessment) and the Appendix is non-mandatory guidance to help meet 1926.65(g) obligations. See the LOI at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28 and the Appendix at 1926.65AppA.

Yes — the appendix states that other tests and other challenge agents may be used to evaluate compliance with 1926.65(g)(4)(ii) and 1926.65(g)(4)(iii); the appendix provides non-mandatory examples but is not an exclusive list (see 1926.65AppA).

Visually inspect all parts to ensure proper positioning and secure attachment, confirm all exhaust valves are not blocked, make sure the suit is completely dry inside and out, and verify repaired components by retesting and recording results per 1926.65AppA.

Before and after each suit test, close off the end of the tubing attached to the suit and confirm the apparatus can maintain three inches water gauge for three minutes to assure the test equipment is leak-tight, as required by 1926.65AppA.

Multiply the test area volume by 0.2 milliliters per cubic foot to get the approximate volume of concentrated aqueous ammonia required to produce about 1000 ppm. This calculation and procedure are described in the appendix method; see the TECP suit ammonia test method in 1926.65AppA.

You should measure the calculated volume from the concentrated aqueous ammonia supply and place it into a closed plastic container until use. The appendix instructs to measure the volume from the supply and keep it in a closed plastic container before bringing it into the test room; see 1926.65AppA.

Place the closed ammonia container, several high-range ammonia detector tubes, and the pump in the clean test pan and locate that pan near the test area entry door so the suited person can reach them. The appendix directs these items be placed in the test pan near the entry door to provide easy access for the suited individual; see 1926.65AppA.

Attach a pre-sealed ammonia indicator strip to the inside of the suit face shield lens and moisten it with distilled water without touching the detector area. The appendix explains to open the strip in clean air, fasten one end inside the face shield, moisten with distilled water, and avoid touching the detector paper; see 1926.65AppA.

If attachment inside the face shield is impractical, you may attach the indicator strip to the outside of the respirator facepiece lens used during the test. The appendix permits attaching the indicator strip to the respirator facepiece exterior when interior attachment presents problems; see 1926.65AppA.

First don the respiratory protective device normally used with the suit, then don the gas-tight totally-encapsulating chemical protective (TECP) suit and verify all intended seals (zippers, gloves, etc.) are fully closed. The appendix instructs wearing the usual respirator before donning the suit and checking that seals are complete; see 1926.65AppA.

You must not plug or block any venting valves on the suit prior to testing. The appendix explicitly warns: DO NOT plug off any venting valves; see 1926.65AppA.

Use an enclosed test room (for example a closet, bathroom, or test booth) equipped with an exhaust fan but do not exhaust air from the chamber during the test because exhaust would dilute the ammonia concentration. The appendix directs that the test room have an exhaust fan but that no air be exhausted during the test to avoid dilution; see 1926.65AppA.

Wait two minutes after pouring the pre-measured concentrated aqueous ammonia into the empty plastic test pan to allow adequate volatilization before measuring the chamber concentration. The appendix requires a two-minute wait (a small mixing fan may be used) prior to taking a reading; see 1926.65AppA.

You must generate a chamber ammonia concentration of 1000 ppm or greater before starting the exercise protocol. The appendix requires the test area reach at least 1000 ppm ammonia before exercises begin; see 1926.65AppA.

The suited person must follow a four-minute exercise sequence: one minute of 15 arm-raising motions above the head; one minute walking in place with at least 15 raises of each leg; one minute of 10 full motions touching the toes (arms from overhead to toes); and one minute of 10 complete standing-and-squatting knee bends. The appendix lists this four-step, four-minute exercise protocol to simulate suit movement and test integrity; see 1926.65AppA.

Stop the test immediately and initiate the post-detection procedures specified in the appendix (sections 6.10 and 6.12), which include exiting the test area and measuring interior suit ammonia concentration. The appendix instructs stopping the test on any color change and following the listed procedures for measurement and exit; see 1926.65AppA.

After exiting the chamber and opening a suit penetration (such as the suit zipper), measure the ammonia concentration inside the suit near that opening using a low-range length-of-stain detector tube or another ammonia monitor; make sure to sample far enough from the chamber to avoid false readings. The appendix specifies using the suit opening to sample interior air and sampling away from the enclosed test area to prevent false positives; see 1926.65AppA.

Any detectable ammonia at or above five ppm by the length-of-stain detector tube (or the detector's minimum detection limit if a different monitor is used) indicates the suit has failed the test. The appendix sets five ppm (for the length-of-stain tube) as the failure threshold and allows specifying lower detection limits when other instruments are used; see 1926.65AppA.

The intrusion coefficient is calculated from the measured test area concentrations and the interior suit concentration (the appendix explains recording the two area concentrations, their average, the interior concentration, and calculating the intrusion coefficient); an intrusion coefficient of approximately 200 or more indicates the suit is suitable for emergency response and field use. See the reporting and pass criteria in 1926.65AppA.

Record a unique suit ID, brand and purchase date, material and special features, description of the test room, brand and dates for ammonia detectors and tubes, sampling pump model, the two test area concentrations and their average, the interior suit concentration, and the calculated intrusion coefficient; also record pass/fail and test date. The appendix’s reporting section lists all required fields for each tested suit; see 1926.65AppA.

If a suit fails, perform a leak check using the pressure test described earlier in the appendix, correct defects, and then retest the suit following the same ammonia test procedure. The appendix directs checking for leaks via the pressure test and repeating the 6.0 procedure if the suit fails; see 1926.65AppA.

The employer is responsible for assessing workplace hazards and documenting PPE requirements, including test results and written certification when PPE is required. OSHA's PPE standard interpretation clarifies that employers must assess the workplace and provide written certification when PPE is required, which supports maintaining the test records required by 1926.65AppA and is explained in OSHA's PPE hazard assessment letter of interpretation (2024-03-28).