Common Dry Riser Defects and How to Fix Them (A UK Engineer’s Guide)
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Common Dry Riser Defects and How to Fix Them (A UK Engineer's Guide)
Dry risers only get tested twice a year — a 6-monthly visual and an annual wet pressure test under BS 9990:2015. Between those dates they sit there doing absolutely nothing, until the fire brigade or a competent person opens the door and finds out whether everything still works.
In our work installing and servicing dry risers nationwide at Viva Fire Protection, the same handful of defects come up again and again. The good news: nearly all of them have a quick, affordable fix if you catch them early. This guide walks through the nine we see most often, what causes each one, and exactly how to put them right.
Why Defects Matter (Beyond Compliance)
Dry risers are there for one reason: to get water to upper floors fast in a fire. Under BS 9990:2015 they must be fully operational at all times, and any fault needs logging, rectifying and retesting before the system goes back into service. A failed annual test doesn't just mean paperwork — it means the system is legally out of use until remedied, the fire service should be notified, and the responsible person carries personal liability under the Regulatory Reform (Fire Safety) Order 2005.
Most defects are also cheap to fix if you catch them at the 6-monthly visual stage. Leave them to the annual wet test and a £5 washer turns into a call-out, a drain-down and a failed certificate.
The 9 Most Common Dry Riser Defects
1. Seized Landing Valve Hand Wheels
What it looks like: You try to open a landing valve for the annual test and the wheel won't budge, or it turns but the valve gate doesn't.
Why it happens: Landing valves sit unused for months at a time. Lime scale builds up on the spindle, gland packing dries out and binds, and corrosion can lock the gate in place.
The fix: A competent engineer should strip the valve, clean the spindle, regrease with a non-petroleum grease, and replace the gland packing. If the gate itself is corroded or scored, replace the whole landing valve with a BS 5041-compliant unit. Prevention is better than cure: exercise every landing valve fully open-to-closed at every 6-monthly visit.
2. Missing or Damaged Caps and Chains
What it looks like: Blanking cap gone, chain snapped, or both.
Why it happens: Theft is surprisingly common (brass has scrap value), along with accidental damage from contractors and general wear.
The fix: Replace the cap and chain. Landing valve caps and inlet breaching valve caps can be slightly different — always try to match to the valve type.
3. Perished Instantaneous Washers
What it looks like: The rubber washer inside the instantaneous coupling is hard, cracked or deformed, so the fire brigade's hose won't seal.
Why it happens: Rubber degrades with age, UV exposure, heat, and ozone. Even if nothing has been connected in three years, the washer is ageing every day.
The fix: Swap the washer. This is a 2-minute job, sets typically cost a few pounds, and every service engineer should carry spares on the van.
4. Gland Packing Leaks
What it looks like: Water weeps out of the landing valve spindle under test pressure.
Why it happens: Gland packing dries and wears over time, especially if the valve has been repeatedly adjusted.
The fix: Repack the gland with suitable packing material and tighten the gland nut incrementally until the leak stops — but not so tight the wheel binds. If the spindle is pitted or scored, the valve body itself usually needs replacing.
5. Corroded Inlet Breaching Valves
What it looks like: Rust, pitting, or seized couplings on the ground-floor inlet.
Why it happens: Inlet cabinets often trap moisture. Without ventilation or drainage, water collects and corrodes the valve over the years. Add any salt-air exposure in coastal buildings and it accelerates.
The fix: Replace the inlet breaching valve with a BS 5041-compliant unit. While the cabinet is open, improve ventilation and check that the drain hole (if fitted) is clear. If the cabinet itself is damaged or rusted through, replace it too — a failed cabinet door is another inspection point.
6. Drain Valves That Won't Close (Weeping)
What it looks like: After draining the system post-test, the drain valve still drips.
Why it happens: Debris lodges on the seat, or the seat itself has become scored over repeated uses.
The fix: Flush the valve by cracking it open and closed several times. If that doesn't clear it, replace the drain valve entirely.
7. Pressure Drop on the Annual Wet Test
What it looks like: You pressurise the riser to 12 bar and the gauge falls below spec within the 15-minute hold.
Why it happens: A joint is leaking, pipework has split, a landing valve isn't holding pressure, or the non-return valve at the inlet has failed.
The fix: Most leaks are at threaded or flanged joints and can be repacked or re-jointed. Split pipework needs cutting out and replacing. If the leak is at a landing valve, either replace the washer/gland or the whole valve. Never sign off a pressure test with a known leak.
8. Cabinet Door Damage
What it looks like: The door won't close, the glass panel is missing, or the signage has gone.
Why it happens: Impact damage from vandalism, cleaners, contractors, or general wear over time.
The fix: Replace the hinges if the door is sound, or the whole cabinet if not. Refit the glass panel and signage — inspectors look for both. Cabinets should be clearly marked "DRY RISER INLET" (ground floor) and "DRY RISER OUTLET" (each floor).
9. Air Valve Faults and Trapped Water
What it looks like: The automatic air release valve at the top of the riser is either seized shut or stuck open. Seized shut, the riser won't vent properly as it fills (you get an air lock and uneven pressure), and it won't draw air in as it drains, so water can stay trapped in the pipework after a test. Stuck open or perished, the valve weeps or leaks water under pressure. You may also find water coming out when you open the drain valve at the base of what should be a dry system.
Why it happens: The air release valve has a float or ball and a small seal that corrode, scale up or perish with age. Separately, water gets into a riser through leaking landing valves, condensation or test water that was never fully drained. Trapped water corrodes pipework, and in cold weather it freezes and splits pipes.
The fix: Drain the riser completely via the drain valve at the base. Clean or replace the air release valve if it's seized, weeping or heavily scaled. It's a low-cost part, so replace it rather than nurse it.
When to Repair vs When to Replace
For most components, the decision tree is simple:
- Washers, caps, chains: always replace, never repair.
- Gland packing: repack first, replace the valve only if the spindle is damaged.
- Landing valves: replace if the body is corroded or the gate is scored. Otherwise service.
- Inlet breaching valves: replace if there's any corrosion; they're a safety-critical component.
- Pipework: repair joints; replace full lengths if there's any split or deep corrosion.
- Cabinets: replace if the door won't close properly.
Every replacement part should be BS 5041 compliant — it's the British Standard for landing valves, breaching valves and associated fittings.
Keeping Records When You Fix a Defect
BS 9990:2015 requires that any defect is logged, remedied, and retested. Minimum records should include:
- Date, time and location of defect (riser reference, floor, valve number)
- Description of the fault with a photo where possible
- Action taken and part(s) replaced (with part numbers)
- Retest result and pressure achieved
- Name and signature of competent person
- New certificate issued
Keep records for at least six years. A clean, up-to-date logbook is what the fire service, your insurer and any incoming facilities manager may look at first.
Frequently Asked Questions
How often should defects be found? A well-maintained dry riser in a modern building should pass its 6-monthly visual with minor housekeeping items. An older system, or one that's been neglected, will typically need 3–5 small remedial parts at the first proper service. After that, a rolling programme of washer and seal replacements keeps it passing.
Can I fix a dry riser defect myself? Simple parts like caps, chains and instantaneous washers are straightforward. Anything involving pressurised water, gland packing, or the landing valve itself should be carried out by a competent person — usually a fire protection engineer or qualified plumber with dry riser experience. The annual wet pressure test is always a competent-person job under BS 9990:2015.
What happens if my dry riser fails the annual test? The system is legally out of service until remedied. Place an "out of service" tag on the inlet, notify the responsible person and the local fire and rescue service, source compliant parts, carry out the repair, retest, and reissue the certificate before returning it to service.
Where can I buy BS 5041-compliant dry riser parts? We stock the full range at dryriserparts.co.uk — landing valves, inlet breaching valves, caps, chains, washers, drain valves and more. All UK-held, quick dispatch on orders before 2pm.
Stock the Parts, Pass the Test
If you manage buildings with dry risers, the single most cost-effective thing you can do is carry a small stock of the most common parts: caps, chains, and washer sets. nb Combined with a rigorous 6-monthly visual, it keeps your annual test results clean and your compliance records tidy.
Need parts fast, or want a competent person to carry out the test for you? At Viva Fire Protection we offer nationwide dry riser servicing, testing and remedial works, and we stock every part we've mentioned in this article at dryriserparts.co.uk.
Related reading
- Dry Riser Maintenance Checklist for UK Facilities Managers
- Dry Riser Testing Requirements Under BS 9990:2015
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Viva Fire Protection Ltd is a UK-wide fire protection contractor. We install, service, test and repair dry risers, wet risers, sprinklers and hydrants for building managers, M&E contractors and facilities teams across the country.