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ISO 15077-10:2014 – Pressure Testing of Isolating Valves for Water Supply: Procedures and Acceptance Criteria
Technical guide to shell test, seat test, and backseat test requirements for compliance with ISO 15077-10:2014
Scope of ISO 15077-10:2014
ISO 15077-10:2014 is an international standard within the ISO 15077 series that specifies pressure testing requirements for isolating valves intended for water supply applications, including potable water, raw water, and treated water systems. It applies to gate, globe, butterfly, and ball valves with nominal sizes DN 15 to DN 1200 and pressure ratings up to PN 40. The standard defines three principal test categories: shell test, seat test (with two subcategories: high-pressure seat test and low-pressure seat test), and backseat test. It also provides acceptance criteria, test durations, and documentation requirements to ensure consistent quality and safety across valve designs.
The scope includes both metal-seated and resilient-seated valves, but excludes valves used in gas distribution, steam, and hazardous fluid services. The standard is intended for valve manufacturers, testing laboratories, and end users who require a uniform method for verifying the pressure integrity of isolating valves before installation or after maintenance.
Tip: When selecting a test pressure for the shell test, always multiply the allowable pressure rating (e.g., PN 16) by 1.5 for the minimum shell test pressure, but never exceed the maximum rated pressure of any non-metallic component.
Technical Requirements
Test Pressure and Duration
ISO 15077-10:2014 sets forth specific pressure values and hold times for each test category. The test medium must be clean water, unless otherwise specified by the manufacturer. The standard references a standard test temperature of 20 °C; corrections for temperature shall be applied if the test temperature deviates. The table below summarizes the minimum test pressures and hold times.
| Test Type | Minimum Test Pressure | Minimum Hold Time (DN ≤ 300) | Minimum Hold Time (DN > 300) |
|---|---|---|---|
| Shell test | 1.5 × PN | 60 s | 120 s |
| High‑pressure seat test | 1.1 × PN | 60 s | 120 s |
| Low‑pressure seat test | 0.1 MPa (1 bar) | 60 s | 60 s |
| Backseat test | 1.1 × PN | 30 s | 60 s |
Note: PN refers to the nominal pressure rating in bars. For example, a PN 16 valve requires a minimum shell test pressure of 24 bar.
Leakage Acceptance Criteria
During the shell test, no visible leakage is permitted through the valve body, bonnet joints, or stem seals. Any weeping or drops constitute failure. For seat tests, the standard divides acceptable leakage into two classes:
- Class A (zero leakage) – Zero visible leakage for resilient‑seated valves and certain metal‑seated valves with elastomeric inserts.
- Class B (controlled leakage) – For all‑metal seats, a maximum leakage rate is permitted, expressed in ml/min per DN (e.g., 0.1 ml/min·DN for DN ≤ 300). The standard includes a table with allowable leakage rates by nominal size.
Warning: Seat leakage tests must be conducted with the valve in the fully closed position and the pressure applied from the upstream side (or both sides if the valve is designed for bidirectional shut‑off). Always ensure that the test pressure is applied slowly to avoid hydraulic shock that can damage sealing surfaces.
Implementation Highlights
Successful implementation of ISO 15077-10:2014 requires careful attention to test setup and documentation. The standard mandates that all test equipment be calibrated to traceable standards with a maximum error of ±2 % of the indicated pressure. Pressure gauges must have a range not exceeding 1.5 times the test pressure to ensure accuracy. The standard also requires that every valve be tested individually; batch testing is not permitted.
For resilient‑seated valves, a “dry” test is recommended for the low‑pressure seat test to avoid water absorption effects that could mask leakage. Additionally, the test sequence is important: the shell test must be performed first to verify the pressure containment integrity before any seat tests are conducted. The backseat test is performed with the valve partially opened to verify that the stem seal withstands full system pressure.
Key Benefit: Compliance with ISO 15077-10:2014 gives manufacturers and end users a recognized benchmark for valve quality. Many water utilities and engineering contractors now mandate this standard in procurement specifications, reducing the risk of in‑service failures and costly downtime.
Documentation is a critical part of the implementation. The standard specifies that each valve must be accompanied by a test certificate that includes: the unique valve identifier, test dates, test pressures, hold times, number of test cycles (if applicable), and the test results for each category. The certificate must be signed by an authorized inspector and, when required, witnessed by a third‑party certifier.
Common Pitfall: A frequent cause of test failure is the misapplication of test pressure for valves that have a lower‑rated secondary end connection. For example, a valve with a PN 40 body but a PN 16 flange must be tested at the higher pressure (1.5 × 40 = 60 bar) only if the flange can withstand it; otherwise, the valve must be de‑rated or tested with the flange replaced by a higher‑rating blind.
Compliance and Certification Notes
ISO 15077-10:2014 does not itself provide a certification scheme; however, it is frequently referenced in ISO 9001‑based quality management systems and in product certification programs such as ISO 17292 (metal ball valves) and ISO 5208 (pressure testing of valves). Manufacturers seeking third‑party certification should ensure that their test procedures align fully with the requirements of this part. Accredited test laboratories can issue statements of conformity, and some national or regional certifications (e.g., WaterMark in Australia, Kiwa in Europe) accept ISO 15077-10 test results as evidence of compliance.
It is important to note that this part does not supersede earlier editions of the standard; therefore, users must verify the publication year (2014) when referencing it. Any deviation from the prescribed test methods (e.g., using air instead of water) must be documented and justified. In cases where a valve has been repaired or refurbished, a full retest according to ISO 15077-10:2014 is required if the pressure‑containing envelope or seat surfaces have been reworked.
Tip: Maintain a clear log of all test equipment calibration certificates. Many auditors will check that the calibration expiry date covers the entire testing period of the valves in question.
Frequently Asked Questions
Q: Is ISO 15077-10:2014 applicable to valves used in fire‑fighting water supply systems?
A: Yes, the standard applies to all isolating valves in water supply networks, including those for fire‑fighting. However, additional requirements from local fire codes (e.g., UL/FM) may also apply and should be considered in conjunction with ISO 15077-10:2014.
A: Yes, the standard applies to all isolating valves in water supply networks, including those for fire‑fighting. However, additional requirements from local fire codes (e.g., UL/FM) may also apply and should be considered in conjunction with ISO 15077-10:2014.
Q: What is the difference between Class A and Class B leakage acceptance?
A: Class A (zero leakage) is required for resilient‑seated valves providing bubble‑tight shut‑off. Class B permits a controlled leakage rate for metal‑seated valves, where some leakage is expected. The choice depends on the service criticality; for potable water distribution, Class A is generally preferred to avoid pressure loss.
A: Class A (zero leakage) is required for resilient‑seated valves providing bubble‑tight shut‑off. Class B permits a controlled leakage rate for metal‑seated valves, where some leakage is expected. The choice depends on the service criticality; for potable water distribution, Class A is generally preferred to avoid pressure loss.
Q: Does the standard require testing both seated directions for bidirectional valves?
A: Yes. For valves designed to seal in both directions, seat tests must be performed from each side separately. The test pressure is applied to the side under test while the opposite side is open to atmosphere to observe leakage.
A: Yes. For valves designed to seal in both directions, seat tests must be performed from each side separately. The test pressure is applied to the side under test while the opposite side is open to atmosphere to observe leakage.
Q: Can the hold times in Table 1 be reduced if the test pressure is increased?
A: No. ISO 15077-10:2014 does not allow pressure‑duration trade‑offs. The specified hold times are minimum times; exceeding them is acceptable, but reducing them is not compliant unless a specific agreement is documented between the purchaser and manufacturer.
A: No. ISO 15077-10:2014 does not allow pressure‑duration trade‑offs. The specified hold times are minimum times; exceeding them is acceptable, but reducing them is not compliant unless a specific agreement is documented between the purchaser and manufacturer.
Article prepared in 2026.