Dry Riser and Wet Riser Systems Explained
Comprehensive fire protection involves much more than just sprinkler systems. If you’re a building or facilities manager, you’ll know there are multiple systems designed to minimise risk and protect residents, visitors, and property owners.
Dry and wet risers are two such systems. But what exactly are they? What’s the difference between them? How do they improve safety? And are they legally required in your buildings? Here’s a clear breakdown from the experts at Eversafe Fire Protection.
Exploring the Similarities
If you’ve ever been confused about dry and wet risers, you’re not alone. The two systems are quite similar. Both consist of a fixed network of pipes within high-rise buildings, designed to give firefighters immediate access to water in emergencies — especially when the building’s height prevents direct use of hydrants or a fire engine’s onboard supply.
Both systems provide a rapid water source for upper floors and must legally be tested every 12 months — a responsibility that typically falls to the property owner or managing agent. At Eversafe, our maintenance service can take care of this testing and certification for you. Read what is involved in an annual dry riser test.
The Difference Between Dry and Wet Risers
Dry Risers
Dry risers are a legal requirement in buildings over 18m tall and are typically used in structures between 18m and 50m due to their operational limitations. These systems feature a network of dry pipes connecting an external ground-floor inlet with internal outlets on upper floors.
During a fire, water is pumped into the network by the fire service, allowing firefighters to attach hoses to the nearest outlet for instant access. Outlets are generally located within every 900m² of floor area — commonly in lobbies, stairwells, and service cupboards. Because pumped pressure decreases with height, dry risers are most effective in buildings under 50m tall. Taller buildings require wet risers for consistent pressure.
Wet Risers
Wet risers are mandatory in buildings taller than 50m, offering superior water pressure at higher levels. This requirement was updated in 2006 (previously 60m). Like dry risers, wet risers use a network of pipes and outlets throughout the building. However, the key difference is that these pipes are kept permanently filled with water under pressure — supplied either via a dedicated storage tank or the mains.
This constant pressurisation ensures firefighters have immediate access to water on all floors. Wet riser systems must deliver at least 1500 litres per minute for a minimum of 45 minutes, providing powerful and reliable suppression capability in tall buildings.
High-Rise Fire Protection
Fire protection in high-rise buildings presents unique challenges. Height impacts both water access and pressure, making the right riser system essential for safety and compliance.
For professional advice or to schedule testing, installation, or maintenance of your riser systems, get in touch with Eversafe Fire Protection at info@eversafefire.com or call 01795 713123.
Related reading: dry riser vs wet riser, the key differences at a glance, and our case study on hydrant testing at Canterbury Cathedral.