Mon - Sat 9:00 - 17:30
Fire extinguishers at high pressure — especially trolley-mounted CO₂, Dry Chemical Powder (DCP), foam, and water types — are lifesaving tools but also potential hazards if overpressurised. To safeguard them, many are fitted with Pressure Safety Valves (PSVs) or rupture disks.
However, these safety devices are often ignored during maintenance because standards rarely specify their testing or replacement requirements. Let’s look at the gaps in standards, causes of overpressure, and best practices organisations should follow.
High Ambient Temperature: Storage near boilers, furnaces, or in sunlight.
Fire Exposure: Heating during nearby fires can cause rapid pressure rise.
Overfilling During Refilling: Reduces vapor space, amplifying pressure rise with heat.
Blocked or Defective Valves: Prevents pressure relief during discharge.
Chemical Decomposition: Some powders/agents can release gases over time.
Cylinder Weakness/Corrosion: Even normal pressures can become unsafe.
IS 2878:2004 (CO₂), IS 15683:2018 (wheeled extinguishers), and IS 2190:2024 (maintenance code) specify hydrostatic testing intervals for cylinders:
CO₂: every 5 years
DCP, foam, water (trolley-mounted): every 3 years
NFPA 10 (USA) requires hydrostatic testing:
CO₂, foam, water: every 5 years
Dry chemical (steel shell): every 12 years
IMO/SOLAS (marine fixed systems): hydro test every 10 years
ASME Section VIII & ISO 4126: require rupture disks/PSVs on pressure vessels, with rated burst/set pressures, but do not give replacement intervals for extinguishers.
👉 None of these standards specify testing or replacement intervals for PSVs or rupture disks on extinguishers.
Since standards are silent, organisations should adopt preventive measures:
Inspection: At every annual maintenance or refill, check PSV/rupture disk condition.
Replacement:
After any actuation or visible damage.
Every 5 years for rupture disks.
Every 5–10 years for PSVs, depending on environment (shorter if in corrosive/humid areas).
Functional Testing (PSVs only): Bench-test during overhaul to confirm set pressure, then reseal or replace.
When servicing any trolley-mounted or portable high-pressure extinguisher, technicians should:
Visual Check – Look for corrosion, cracks, tampering, or leaks on PSV/rupture disk.
Seal Integrity – Ensure burst disk seals are intact and not deformed.
Thread & Fittings – Inspect for cross-threading, damage, or leakage marks.
Set Pressure Verification (for PSVs) – Confirm calibration where facilities exist.
Replacement – Change PSV/rupture disk if:
Expired as per preventive schedule.
Found corroded/damaged.
Activated or suspected of leaking.
Documentation – Record device type, set/burst pressure, inspection date, and next due date.
High-pressure extinguishers — whether CO₂, DCP, foam, or water — depend on PSVs or rupture disks to prevent catastrophic failure. While Indian and international standards specify hydrostatic testing intervals for cylinders, none give a mandatory interval for PSV or rupture disk testing/replacement.
Therefore, adopting best practices is essential: replace rupture disks every 5 years, test/replace PSVs every 5–10 years, and always check safety devices during maintenance. This proactive approach goes beyond compliance, ensuring reliability when it matters most.
👉 For more such insights, follow us on LinkedIn, and consult us to implement fire safety best practices in your organisation.
We offer a full suite of HSEFS services designed to address your specific challenges and goals : HSE Consulting & Advisory, HSE Auditing & Assurance, HSE Training & Development, Implementation & Support, Environmental Services
Copyright 2025. Agni Raksha Niti Engineering Consultancy Services Pvt. Ltd. All Rights Reserved.