Special and Safety Valve Tests: Fire, Cryogenic, Emissions, Type Test
Special tests differ from routine pressure testing not because the bench is more expensive, but because the sample’s state is irreversible. A valve that has been through a fire cannot then be cryogenically tested; a graphite packing measured for fugitive emissions changes its friction the moment it is disturbed. Sequence, sample count and re-test points matter more than bench specifications.
This cluster covers fire, cryogenic, fugitive emissions, type testing, safety valves, liquid cooling and aggressive media — all of which come down to the same three questions: what to run first, how many samples, and what counts as done.
1. Sequencing the special tests
| Test | Basis | Sample altered? | Recommended order |
|---|---|---|---|
| Fugitive emissions | ISO 15848-1, API 624/641 | Yes (packing bedding-in) | First, before any strip-down |
| Cryogenic | ISO 28921-2, BS 6364, GB/T 24925 | Yes (seat condition after deep cold) | Not after fire |
| Fire | ISO 10497, API 607 | Yes, irreversibly | Last; judged on leakage only |
| Type test | TSG D7002-2023 | Not necessarily | All sub-items allocated across one sample set |
Get the order wrong and the earlier data is wasted. The most common waste is running fire first and emissions second — after the burn the packing has changed and the emission figure means nothing.
2. Find the article by question
Fire and cryogenic
- Fire testing: ISO 10497 and API 607 compared — the criterion is whether it still shuts off, not how it looks
- Cryogenic testing: ISO 28921-2, BS 6364 and GB/T 24925 compared — cooling medium, soak time, cold torque
- Thermal cycling machines: defining the conditions and the acceptance
Fugitive emissions and micro-leakage
- Fugitive emission testing: choosing between ISO 15848-1/-2 and API 624
- Air tightness tests that keep failing? Five leak paths to check first
Type testing and safety valves
- Type testing under TSG D7002-2023: items, sampling and coverage — how far one model covers
- What a safety valve bench measures: set pressure, reseat pressure and seat tightness are three answers
- Deciding safety valve test items: the scope of set, reseat and tightness
- A safety valve performance test programme: flow and acceptance boundaries
- Automatic safety valve testers: range, safety envelope and acceptance
- Temperature and pressure relief valve benches: conditions, response, acceptance
Liquid cooling and aggressive media
- Liquid-cooling valve test plans: parts under test, medium, condition envelope
- PICV testing for BESS liquid cooling: conditions and a verification matrix
- Leak testing liquid-cooling valves in data centres: method by part and allowable leak
- Choosing a liquid-cooling valve bench: requirement envelope and prototype acceptance
- Liquid-cooling quick couplings: insertion, leakage and post-cycle checks
- Clamp ball valves in liquid cooling: structure and what to test
- Chemical valve test plans: media compatibility, pressure envelope, special risks
- Choosing a temperature-humidity chamber: from sample load to acceptance conditions
3. Three misjudgements
Running every special test on one sample. Fire, cryogenic and emissions conflict: emissions needs a bedded-in packing, cryogenic needs a fresh seat, fire destroys the packing. That is why type-test sampling rules specify a sample count. Short of samples, the data has to be cherry-picked.
Reading “no leak” as a pass. The fire criterion is leakage during the burn and after cool-down, not appearance; the cryogenic criterion includes operating torque at temperature, not only tightness. Judging on leakage alone drops half the criteria.
Writing coverage wider than it is. TSG D7002-2023 coverage has hard boundaries: pressure, size, temperature, construction. Using a DN50 result to cover DN300, or a soft-seat result to cover metal-seat, gets rejected on review. Write the coverage table structure by structure, class by class.
4. Configuring the bench
Special tests rarely run on one machine. The practical split is a general bench for routine pressure and tightness, and dedicated tooling for the specials. Fire needs a burn pit and thermocouples, cryogenic needs a cold source and insulated spool, emissions needs a fixed-volume sampling enclosure — in all three, the tooling matters more than the host machine.
- Valve comprehensive test bench — routine pressure, tightness, flow, torque and life on one frame, with special tooling swapped in
- Pipe and connection leak test bench — screening stage for emissions and liquid-cooling leaks
- Manifold comprehensive test bench — separate circuits for assembly and branches
Continue by test item
These clusters are grouped by test item rather than by standard number. The other four:
- Pressure and tightness — shell, seat and air tightness
- Flow and control performance — Cv/Kv, PRVs and TMVs
- Life, torque and fatigue — fix the conditions first
- Certification and market access — EU, US and China
Not sure about the test pressure yet? Use the valve test scope configurator — pick valve, size, class and standard, and it returns shell and seat pressures, hold time and a bench list you can email.
Related test equipment
Each test above maps to a bench. Pick by valve type and by the item you need to prove:
- Valve comprehensive test bench — pressure, tightness, flow, torque and life cycling on one clamping system
- Pipe and connection leak test bench — pressure-decay and helium methods, judged against a leak-rate limit
- Manifold comprehensive test bench — separate circuits for the assembly and each branch, itemised records
- Valve testing equipment range — browse all models by valve type and test item