As-Received Pop Pressure

PRD inspection aid — determine, record, and investigate the as received pop pressure

1. Valve & Test Setup

Valve / PSV Tag

Service

Test Date

Set Pressure (psi)Required — this tool is set to evaluate against set pressure.

CDTP (psi)Use the value required by the applicable procedure.Required — this tool is set to evaluate against CDTP.

Pressure Unit

psi is the default. Switching units converts entered pressure values rather than reinterpreting them.

As-received evaluation basis

The supplied evaluation script defaults to CDTP.

Applicable code (Ref. for reporting only )

Does not change this API RP 576 evaluation logic.

Failure-to-open threshold (%)

Default 150%; supplied text also cites 130% for API 581. Use the owner-operator / approved procedure.

Calculated tolerance band

Enter CDTP / set pressure.

Supplied tool logic: ≤70 psig → ±2 psi; >70 psig → ±3%.

Valve received extremely fouled/dirty — actuation may damage the seatsCheck only when that condition actually applies.If checked, the as-received test may be waived and the inspection interval reduced instead. The valve should be found clean at its next inspection; if it is not, shorten the interval again or take other measures to reduce fouling.

2. As-Received Test 1

Wherever possible, test before cleaning. The first pop is the as-received value of record.

Seals checked

Pressure set-screw cover seal and blowdown-ring screw cover seal.

Test 1 result

Test 1 Pop Pressure (psi)First observed relief pressure.Required — enter the Test 1 pop pressure.

4. Evaluation Result

The evaluation updates automatically. It does not replace the governing procedure or authorized test limit.

PENDINGEnter the required data.

Enter the valve/test data. The tool will identify whether the first pop is within tolerance, requires Test 2, is below tolerance, or reaches the configured failure-to-open threshold.

Tolerance band—

Test 1 % of basis—

Failure-to-open threshold—

First-test pop—

Recorded as-received result

—

Failure Mode / Investigation Record

Observed failure mode

Inspection interval / corrective action

Notes

What the result means

High first pop + in-tolerance Test 2: deposits may have delayed the first opening; first-test pressure remains the recorded as-received result.
High first pop + high Test 2: investigate the original setting or a setting change during operation.
Low first pop: possible weakened spring, improper prior setting, seat damage, or setting change during operation.
No pop at threshold: classify as stuck shut / failed to open and discontinue the test, subject to the approved test limit.

5. Inspection Report

A concise copy-ready record of the entered inputs, decision path, and result.

As-Received Pop Pressure Inspection Report

6. As-Received Test Procedure

① Check sealsConfirm the pressure set-screw cover seal and blowdown-ring screw cover seal are intact before the valve is dismantled.

② Mount & pressurizeMount the valve on the test stand/block; slowly increase inlet pressure.

③ Record first popThe pressure at which the valve relieves is the “as-received” pop pressure — this first result is always the one recorded.

④ Interpret / retestCompare to the CDTP tolerance band; retest only if the first pop is above tolerance, per the decision logic below.

Before cleaning: As-received testing should be done before cleaning wherever possible. Cleaning deposits beforehand can remove material that was preventing the valve from opening at set pressure, masking the true as-received condition.

For acid/caustic/toxic services, the test can be performed with an on-site test stand or a contracted portable test stand.

7. How to Interprete The Result?

Pop at or near CDTP

If the valve pops within the applicable tolerance band on the first try, no further testing is needed — that first result is the as-received pop pressure.

Pop above CDTP

Test a second time. A second pop near CDTP suggests deposits may have delayed the first opening. If Test 2 remains outside tolerance, investigate the setting. The first test remains the recorded as-received pop pressure.

No pop up to the threshold

A valve that does not relieve by the selected threshold is considered stuck shut / failed to open — discontinue the test, subject to the approved test pressure limit.

Pop below CDTP

Possible causes include a weakened spring, improper prior setting, seat damage, or a setting change during operation. No retest is prescribed in the supplied procedure; the first result is recorded as-received.

Owner-user criteria: The owner-operator should define the criteria that constitute an “as-received” pop-test failure and may use different investigation rigor depending on failure severity and application criticality.

8. Failure Mode Reference

An “as-received” pop test can fail in a number of ways. Root cause should be investigated and a corrective action plan developed as appropriate — potentially including a reduced inspection interval and/or design changes.

Failure mode	Simple field meaning
Stuck shut / fails to open	Valve does not relieve by the applicable failure-to-open threshold.
Device partially opens	Valve does not reach full lift.
Opens above set pressure tolerance	Pop pressure exceeds the applicable tolerance band.
Leakage past the device	Valve is not tight below set pressure.
Spurious / premature opening	Valve relieves well below CDTP.
Device stuck open	Valve fails to reseat after testing.

9. Field Inspection Checklist

Confirm CDTP / set pressure nameplate or datasheet
Check seals pressure set-screw cover and blowdown-ring cover
Select applicable code context Section I / Section VIII Div. 1 / other program
Assess as-received fouling condition waive test only when extreme fouling may damage seats
Mount valve & slowly increase inlet pressure within the approved test limit
Record first pop pressure or maximum test pressure if no pop
Retest if required only after a high first pop
Photograph valve / nameplate document the as-received condition
Evaluate & record result including failure mode / investigation action

Progress:

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10. Code & Inspection Context

Use this quick reference to keep three different questions separate: valve set-pressure performance, vessel overpressure limits, and the API RP 576 as-received investigation.

Topic	ASME Section I	ASME Section VIII Div. 1	API RP 576 — As-received pop test
Primary purpose	Pressure-relief valve operation for Section I boiler/steam-service applications.	Protection of pressure vessels; UG-153 addresses allowable overpressure, while UG-155 addresses settings/tolerances.	Determine what the relief valve actually did when received, before cleaning or servicing changes its condition.
Reference pressure	Primarily set pressure for the PG-72 performance requirements.	Can involve MAWP for vessel overpressure protection and set pressure for PRV settings.	CDTP / set pressure, as applicable to the owner-operator evaluation procedure; the tool defaults to CDTP.
Set-pressure tolerance	≤70 psi: ±2 psi; >70–≤300 psi: ±3%; >300–≤1,000 psi: ±10 psi; >1,000 psi: ±1%.	UG-155: ≤70 psi: ±2 psi; >70 psi: ±3%, subject to specific exceptions.	The owner-user should define the as-received failure criteria. This tool uses the supplied ±2 psi / ±3% evaluation logic as the default calculation.
Full-lift / operation	Steam: full lift ≤3% above set pressure; minimum blowdown 2 psi or 2%, whichever is greater. Liquid: full lift ≤3 psi or 10%, whichever is greater.	UG-153 addresses overpressure protection, not a generic “pop tolerance.”	The focus is the first as-received pop and, when the first pop is high, the controlled second test.
Overpressure limit	Not the focus of this table’s as-received evaluation.	Normal UG-153(a): pressure rise limited to 10% or 3 psi above MAWP, whichever is greater, subject to listed exceptions.	Not an API RP 576 pop-pressure tolerance. Do not use the UG-153 overpressure allowance as the pop-test acceptance criterion.
Failure to open	Use applicable Section I requirements and the approved test procedure.	Use applicable Section VIII / Section XIII requirements and the approved test procedure.	The owner-user defines failure criteria. The supplied procedure gives 150% as a common default stuck-shut threshold; API 581 is cited in the supplied text at 130%.

Key distinction: set-pressure tolerance, full-lift performance, and vessel overpressure limits are not interchangeable. The API RP 576 workflow here is specifically about the as-received first pop pressure and what it tells the owner-operator about condition and future inspection.