Fires can spread rapidly. In high-rise buildings, the risk of rapid-fire spread increases along with the potential danger of people becoming trapped in burning rooms, unable to evacuate safely. Large buildings also pose a unique challenge: if a fire starts suddenly on the top floor, how can you quickly and effectively target the affected area from the bottom of the building? The solution is simple – by using dry riser and wet riser systems.

In this comprehensive guide, we will look at these two firefighting systems. We will also look at the importance of servicing dry and wet risers – and how OHEAP’s expert engineers can help you do just that.

What is a Wet Riser?

A wet riser is also a system of valves and pipe work designed and used to distribute water across multiple rooms of a large building. However, unlike dry risers which remain empty until needed a wet riser system stays constantly charged with water.

When you need to pump water up a tall building, it takes a lot of pressure because you’re working against gravity. That high pressure can pose a risk of damaging the pipes or equipment. To solve this, a water tank may be installed near the top of the building (typically in the roof area). This tank feeds water into a wet riser.

The steel tube of the wet riser that runs the length of the building has a constant pressurised supply of water. Because the riser is already full, when you need water (either for sprinklers or fire hoses), you don’t have to pump it up from the bottom. You just need a little extra pressure to move it out of the riser. This pressure is much less (and much safer) than if the riser were empty. This is why wet risers are specially designed to protect buildings over 50 metres tall.

What is the Difference Between Wet and Dry Risers?

There are three main differences between wet and dry risers:

1. Water Supply: Wet risers have a constant supply of water. But dry risers are not equipped with water and therefore require the fire services to connect the system to a water source. This water source could be a fire hydrant or a fire engine.

Do Dry Risers and Wet Risers Need Servicing?

Yes – servicing your dry and wet risers is essential to ensure the equipment works in a fire.

Servicing proactively maintains the quality of your fire safety equipment to maximise your protection. Several factors can affect the quality of your dry and wet risers:

1. Vandalism: Dry risers and wet risers are unfortunately accessible to the public. This increases the risk of vandalism or tampering with the equipment. Servicing alerts you to any developing damage before it can become a problem.

How Often Should Dry Risers be Serviced?

BS9990:2015 illustrates that your dry riser system needs a visual inspection every 6 months. Alongside this, they require annual pressure tests.

Dry risers should be serviced regularly to check for potential damage or developing hazards. The goal of servicing is to identify faults in your fire safety equipment that may impact the quality of your fire protection. The more regularly and thoroughly equipment servicing is performed, the more you can trust in the fire protection your equipment should provide.

What is involved in Servicing Dry Risers and Wet Risers?

Servicing dry risers and wet risers is done either via visual inspections or full pressure inspections. The purpose of servicing your dry or wet riser system is to ensure valves, inlets, outlets and pipes are not leaking, blocked or damaged.

OHEAP’s fire safety experts streamline the servicing process and assist every step of the way. Here’s what servicing your dry and wet risers involves.

Visual Inspections

A dry riser visual inspection is performed by an expert engineer every six months. The goal is to identify damage, remove obstructions and ensure that the system is in good order.

During a visual inspection, an expert engineer checks the valves, inlet and landing valves to ensure they open and close. A visual inspection also checks that the seal is in place and is greased.

Full Pressure Inspections

Also known as a hydraulic or wet test, this is where the dry or wet riser system is pressure tested.

A compressor is attached at the inlet, and water is added to simulate what the brigade would do in an emergency. The system is put under full pressure load, and then all the valves and pipework are checked for leaks. If everything is working as it should, the pressure is released, and the system is drained down.

What Are the Legal Requirements of Servicing Dry and Wet Risers?

In the UK, the legal requirements for dry and wet risers are covered under:

• The Regulatory Reform (Fire Safety) Order 2005: This essentially details that the maintenance of dry or wet risers fall to the building owner or responsible person.

• BS9990:2015 (Code of Practice for Non-Automatic Fire-Fighting Systems in Buildings): This document gives technical guidance on how to sufficiently install, maintain and test your dry or wet risers.

They also detail that a visual assessment of your dry or wet riser system must be performed by a competent person every 6 months, and a full flow and pressure test must be conducted annually. Following these regulations ensures your wet and dry risers are both reliable and functional.

Conclusion – The Importance of Servicing Dry and Wet Risers

Dry risers and wet risers are the most effective way to directly deliver rapid fire suppression to multiple rooms of high-rise buildings.

Fires can be unpredictable. That’s why it is important to always be prepared for such an emergency. While investing in the right fire safety tools helps create immediate fire protection, servicing gives you the information to assess and maximise the protection of your building. Servicing your dry and wet risers is a legal requirement. It also prevents the equipment from failing when you need it to work the most.

Contact OHEAP today to service your equipment and invest in your building’s fire protection.