A logistics distribution centre is in a different fire-scenario class from an office or a care environment. Racks up to 12 m, dense flat roofs, combustible material (cardboard, plastic packaging) and heavy mechanical ventilation make the standard detection strategy unfit. Below is how we approach DC projects.
1. The core problem: smoke dilution
In a high-bay warehouse, smoke rises vertically first, then mixes with large air volumes, and is then pulled away by HVAC or natural ventilation. A conventional point detector at roof height only sees alarm concentrations once the fire is already substantial — and by then it is too late for an adequate response.
2. What NPR 5310 and NEN 2535 prescribe
For warehouse environments a combination is typically deployed:
- Aspirating detection (ASD) for the rack aisles and specifically for cold zones / mezzanines — sensitivity up to 100× higher than passive point detection
- Beam smoke detection across large flat areas — a transmitter/receiver pair monitoring a smoke line over tens of metres
- Conventional optical detection only where air velocities are low (office box inside the warehouse, canteens, changing rooms)
NPR 5310 gives a per-building-type guide; NEN 2535 fixes the formal requirements for the installation.
3. ASD class selection
NEN-EN 54-20 defines three ASD classes. For a DC the choice typically lies between:
- Class A — very high sensitivity, for mission-critical zones (high-value goods, cold storage, critical compartments)
- Class B — elevated sensitivity, for standard rack warehousing
Class C — comparable to conventional point detection — is for most DC applications insufficient.
4. Engineering points to watch
Pipe layout follows the air-flow profile. Sampling holes are placed above rack aisles, not in the middle of a rack. ASD above a rack that is always full adds no value — but above the aisle where the smoke plume actually passes, it does.
Detection in cold storage requires isolating the central unit. The detector block itself must stay at temperature; only the pipe network enters the cold space. This prevents condensation and substantially extends the central unit's lifespan.
Wattage allocation per zone. A large DC typically has multiple ASD units — consider one unit per fire compartment rather than one unit for the whole building, so that maintenance / outage of one unit does not disable the whole detection.
Integration with the smoke ventilation system (RWA). In a real fire RWA hatches must open to vent smoke. ASD alarm triggers RWA — the wrong coupling means either false alarms that open hatches or a real fire trapped in its own smoke.
5. Evacuation alarm — phased or simultaneous?
A DC may have 50 to 500 people on site at any given moment — sometimes two shifts, sometimes one. The OAI strategy depends on:
- Number of people on site during peak moments
- Number of escape routes and their capacity
- Type of goods (hazardous materials demand faster evacuation)
- BHV organisation (number of responders, response time)
In most DC projects we see simultaneous evacuation alarm with live voice messages — not just a tone, but specific instructions. This shortens the average evacuation time substantially.
6. Inspection and certification
High-detection installations such as ASD require specialist inspection. Not every inspector has experience with aspiration systems. During engineering we account for:
- Availability of inspectors with ASD expertise
- Functional test protocols (smoke generators per manufacturer specification)
- Number of required alarm points per zone to demonstrate full coverage
Closing
Fire safety in a DC is risk management at building level — stock value, customer SLA, operational continuity and insurance cover all intertwine. The detection system is the base infrastructure that makes the rest possible.
Do you have a new or existing DC where fire safety needs review? Schedule a site visit — we assess the existing installation and propose a substantiated plan.