In rack sprinkler systems: Fire safety in tiered storage

From apartment complexes to shopping mall parking and industrial storage, tiered engineering makes smart use of vertical space. Yet when it comes to stacked industrial storage, there are drawbacks for fire safety and suppression in smart use of space. Should a fire break out, storage racks may be tricky to reach. In rack sprinkler systems luckily provide dependable fire suppression. 

What are in rack sprinkler systems and their advantages over ceiling sprinklers?

In rack sprinkler protection consists of a network of piping installed to cover key vulnerable points strategically. This differs from traditional ceiling sprinklers which create a deluge from above instead of drenching fires directly where they have broken out. 

The benefits of in rack sprinkler system design

1. Early detection and suppression

Over time, industrial facilities have been built taller to accommodate large storage requirements. Ceiling sprinkler systems (traditionally designed for smaller facilities) may struggle to detect fires before they have spread across aisles and reached a certain size (Steve Wolin, ‘The Return of the In-Rack Sprinkler’). 

The advantage of in rack sprinkler protection is that early detection and activation may happen much faster. A fast-acting system could help to save perishable goods and expensive machinery and infrastructure that would be costly to replace or repair. 

2. Lower water consumption/demand

Ceiling sprinkler systems’ efficiency decreases with building height (more water is required at a higher rate of flow to ensure sufficient dampening). The in rack sprinkler system type is water-wise due to supplying fire suppression exactly where it is urgently needed. This reduces water wastage as well as the risk of water damage where dampening is not required. 

3. No building height limitations

In industrial spaces protected by ceiling sprinklers, there are regulations limiting building height according to the efficacy of the installed fire suppression system. 

There is no building height restriction for in-rack systems, as piping may be laid throughout racks as required. This makes in rack sprinkler protection an adaptable, flexible fire suppression solution that scales with facility growth. 

What in rack sprinkler system type fits which environment?

There are several types of in rack sprinkler protection:

Wet pipe sprinkler systems

This is the most common type of sprinkler system. In this type, piping is constantly filled with water. Although this is the most reliable and cost-effective type (according to the National Fire Protection Association), it is not always the appropriate solution. In sub-zero storage environments, there would be risk of water in the pipes freezing, causing pipes to burst. These and other specialised environs may require dry sprinkler systems.

Dry pipe systems

With the dry in rack sprinkler system type, water is held behind a dry pipe valve and released upon fire detection, rather than pipes being constantly filled with water. 

An important requirement is that the inlet area is above freezing temperature so that water does not freeze before it is released and may flow quickly to the system’s sprinklers. 

Pre-action sprinkler systems

This type of in rack sprinkler system design is the most complex. Unlike wet and dry systems, a specific event (or events) must happen before water is released into the system. There are three kinds of this system type:

• Non-interlock: Either the triggering of detection devices or automatic sprinklers causes the system to fill with water
• Single interlock system: the triggering of detection devices only causes the system to fill with water
• Double interlock system: The pipes only fill with water when detection devices are activated AND automatic sprinklers are activated

Foam-water sprinkler systems

These systems use a mixture of water and foam concentrate so that a foam spray is released instead of water. These systems are particularly effective in environments where flammable goods or materials are stored. 

Deluge sprinkler systems

Like in dry pipe systems, there is no water stored in the piping of a deluge system. Instead, the system is connected to a dedicated water supply. When a fire is detected, water is released to all open sprinkler heads. 

How to know which in rack sprinkler system type is right for your facility

It is best to schedule an inspection of your facility by a registered technician who will be able to advise you on the best system for your space (as well as any repairs or replacements required for existing fire suppression systems, if conducting a full inspection). 

How often should in rack sprinkler systems be inspected? 

Sprinkler systems should be inspected weekly by a competent member of staff or by an ASIB-listed inspection service provider. 

Contact ERF for certified in rack sprinkler system design as well as installation, servicing, and inspection. Piping is manufactured off-site for faster turnaround and minimum disruption, and epoxy-coated for durability. Contact East Rand Fire for a quote today.