FM Global DS 4-4N: Standpipe and Hose Systems Summary

Standpipe and hose systems are the fixed installations that let people fight a fire by hand: standpipe risers, hose valves on each floor, hose reels and cabinets, and fire service inlets. Sprinklers control the fire; final extinguishment, overhaul and reaching places sprinklers cannot are often done with hose. FM Global DS 4-4N Standpipe and Hose Systems covers when these systems are needed, how they should be supplied and how their reliability is kept.

Scope: Risers, Hose and Fire Service Connections

The data sheet covers wet and dry standpipes, small internal hose stations, the larger hose valves used by the fire service, and the water supply and valves feeding them. Terminology differs between countries; the table below maps the terms most often met on site:

Key Loss-Prevention Principles

Hose does not replace sprinklers

For FM, manual firefighting complements automatic protection. The idea that an area can be "covered by hose" does not remove the need for sprinklers. The value of hose lies in speeding up final extinguishment once sprinklers have controlled the fire, in attacking small fires early and in giving the fire service a dependable water point.

Define who will use it

A hose station is only as effective as the person holding it. In the FM approach, internal hose stations make sense where a trained emergency response team exists. An untrained person approaching a fire with a large hose is both ineffective and at risk. So the design starts with "who will use this hose?", and hose size, length and location follow from the answer.

Don't starve the sprinklers

Where hose is fed from the same supply as the sprinklers, hose use can reduce sprinkler pressure. Hose flow is therefore added to the sprinkler demand as a hose allowance, and the supply and pump are sized for the total. Connection points between standpipes and sprinkler mains, and the valve arrangement, should be set up so that a failure on a hose line cannot cut the sprinkler supply.

Valves and supervision

Control valves feeding standpipes and hose stations should be supervised or locked open, just like sprinkler valves. A closed standpipe valve means the fire service finds no water on the floor — and that only comes to light during a fire.

Pressure management

In tall buildings, pressure at lower-floor hose valves can exceed safe handling limits. Pressure-regulating devices solve this but bring their own risk of drifting settings and failure. They must be verified by periodic flow testing. On the FM side this is read together with DS 3-11.

Freezing and physical protection

Unheated stair shafts, ramps and external risers are exposed to freezing and need dry standpipes or heating. In warehouses with forklift traffic, hose cabinets and risers need protection from impact.

Notes for Warehouses and Industrial Sites

In large warehouses the most important job of hose is extinguishing fire that remains deep inside racks after the sprinklers have controlled it. This often takes a long time and involves unloading the racks. Access from hose stations to the rack aisles, hose on both sides of compartment doors and hose lengths that reach the furthest point therefore matter. On industrial sites hose may be used with a foam branch pipe for ignitable liquid spills, in which case foam concentrate and an inductor must also be planned. Joint exercises so the fire service knows the site's hydrants and standpipe connections fit the general FM emergency response approach. Finally, keeping hose stations clear of racks, pallets and machinery should be part of daily checks; a blocked cabinet is as good as none in a fire.

How It Differs from NFPA 14 and EN 671

NFPA 14 sets out standpipe classes and hydraulic criteria in detail: the commonly used baseline values are 6.9 bar (100 psi) residual at the most remote 65 mm outlet with 1893 L/min (500 gpm) for the first Class I standpipe, and 4.5 bar (65 psi) at 379 L/min (100 gpm) for Class II hose. EN 671 is a product standard for the hose reel or hose system itself (hose, nozzle, reel); installation criteria usually come from national regulations. In Turkey the location and number of hose cabinets are set by the national fire regulation (BYKHY).

The FM difference is that it assesses standpipes and hose in terms of sprinkler performance and the integrity of the water supply. The point is not more hose stations, but hose that can be used by the right people, from supervised valves, without weakening the sprinklers.

Practical Checklist

• Who will use the hose (fire service, emergency team, occupants) is defined.
• Hose flow is added to the sprinkler demand as a hose allowance.
• The standpipe feed arrangement prevents a hose-line failure from affecting the sprinklers.
• All control valves are supervised or locked open.
• Pressure-regulating devices are set and verified by flow test.
• Unheated sections have freeze protection.
• The fire service inlet is accessible, signed and compatible with local couplings.
• Hoses, nozzles and cabinets are inspected periodically.

Frequently Asked Questions

Does a sprinklered building still need hose stations?

National regulations usually require them. For FM, hose complements sprinklers; it is valuable where a trained team exists, but it never reduces the sprinkler criteria.

Why is a hose allowance added to the supply?

In a fire, sprinklers and hoses run at the same time. Without the allowance, sprinkler pressure falls when a hose is opened and the design density is lost.

What is the difference between a wet and a dry standpipe?

A wet standpipe is permanently full of water and ready for immediate use. A dry standpipe is empty and is charged from the fire service inlet or a remotely operated valve. Dry standpipes suit areas at risk of freezing.

Where should hose stations be located?

The general logic is protected positions the fire service also knows, such as stair shafts and compartment doors, so whoever attacks the fire advances with a safe escape route behind them.

Why must pressure-regulating valves be tested?

Their settings can drift or they can stick. Only a test under flow shows the real outlet pressure.

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