10 inputs determine the right system safety valve.

A distributor-facing pre-quote checklist. If the customer answers most of these at the first call, the second call is the quote.

1. 01
   What's the vessel's MAWP (Maximum Allowable Working Pressure)?

   Read from the ASME nameplate on the receiver or aftercooler. The relief valve set pressure must be at or below MAWP — never above, never at "what the customer is used to running." A relief valve set above MAWP is not a safety device; it's a sticker on a bomb.
2. 02
   What's the upstream compressor's maximum SCFM at the relief set pressure?

   The relief valve's relieving capacity must equal or exceed this. An undersized valve opens on schedule but can't vent fast enough to stop the pressure rise — the tank still over-pressures while the valve sits open and useless. This is the most common spec error on receiver relief quotes.
3. 03
   What's the local Authority Having Jurisdiction's recertification cycle?

   National Board inspection programs typically run on a 3–5 year cycle, but state and municipal AHJs vary. Confirm before quoting whether this is a new install, a recertification, or a failed-test replacement — the documentation requirements differ, and the customer needs the certificate of conformance from the right authority.
4. 04
   For check valves — what's the compressor type and discharge temperature?

   Reciprocating compressors run 300–400°F discharge air and require a hot-discharge-rated valve (Conrader piloted to 400°F, in-line / in-tank to 450°F). Rotary-screw runs 180–210°F and tolerates general-service valves to 225°F. A general-service valve on a reciprocating discharge degrades thermally within months.
5. 05
   For check valves — what's the discharge port connection size?

   Must match the compressor discharge or receiver inlet exactly. NPT, BSPT, compression-tube, and SAE 45° flare connections are all common depending on the compressor or vessel. Capture the size and thread standard from the existing fitting or the OEM service manual before quoting.
6. 06
   Standalone check valve or combination unloader-check unit?

   Many packaged rotary-screw compressors integrate the discharge check, minimum-pressure valve, and unloader into a single piloted unit; replacement requires the matched combination unit, not a standalone check valve. Pull the OEM service manual or photograph the existing assembly — combination units are visually distinct (multi-port body with pilot line attached).
7. 07
   ASME UV stamp + National Board number — confirmed?

   Every relief valve quoted for a code vessel needs both. A non-ASME "lookalike" valve fails inspection, voids insurance, and is a five-figure-per-violation OSHA citation under 29 CFR 1910.169. Verify on the valve nameplate, not the spec sheet. Import-tier compressor packages sometimes ship with non-compliant valves — replace at install.
8. 08
   New install or replacement — and is this a failed lift-test?

   Replacements match the existing set pressure and connection; new installs are sized fresh to vessel MAWP and compressor SCFM. A failed lift-test (valve won't seat, weeping under normal operating pressure, or won't open at the test point) is an immediate replacement — the valve is no longer code-certified regardless of how recently it was installed.
9. 09
   Body material — brass standard or stainless for the environment?

   Brass is the air-service default and the right call on 90%+ of quotes. Stainless steel is required for wash-down, food-zone, or corrosive environments — bakery, dairy, pharma, marine, outdoor coastal installs. Stainless adds 30–60% to the line; spec it where the environment demands it, not as a default upgrade.
10. 10
    Is the annual lift-test service attached?

    For customers with a service-route relationship, the manual lift test is a 30-second job on the same PM visit as the separator change and oil change. Attaching it converts replacement from "discovered failed at next inspection" to calendar-driven proactive replacement — and it's the entry point for the recertification revenue line every 3–5 years.