Map airflow before the pipe network
Document hot and cold aisles, rack exhaust, CRAC or CRAH return air, ceiling voids, floor plenums and every relevant operating mode.
Application · Data centres
Aspirating smoke detection for data centres
A data-centre ASD design should start with airflow and protection objectives, not floor area. Depending on risk and HVAC operation, sampling may be placed at room level, in CRAC or CRAH return air, at cabinet exhausts, or in ceiling and floor voids. Normal, standby, shutdown and incident modes must all be checked.
Risk conditions that
change the design
The sampling network must respond to the real environment and operating modes.
- 01Smoke dilution caused by high air-change rates
- 02Negative pressure at server cabinets
- 03Loss of return-air performance during HVAC shutdown
- 04High cost of interruption, testing and false alarms
Design priorities
Resolve these conditions before model and network confirmation.
Separate room and return-air objectives
Return-air sampling can respond quickly while the air system is operating, but it may need complementary room or cabinet sampling when airflow changes.
Verify cabinet pressure
Cabinet fans can create pressure conditions that oppose sampling. Confirm the hole position and response with a representative functional smoke test.
Keep maintenance accessible
Locate the detector, filters, isolation and test points where service can be completed without unnecessary operational disruption.
Protection layers
Each layer should have a defined detection and response purpose.
Room-level sampling
Provides general room protection. Sampling positions should follow ceiling, void, return-air and high-air-change conditions rather than copying point-detector spacing.
Return-air sampling
Samples smoke transported towards CRAC, CRAH or central return air. It can provide an early response but depends strongly on equipment operation and dilution.
Cabinet-level sampling
Capillary tubes or local holes can sample high-value cabinets and electrical enclosures. Fan pressure, exhaust direction and door-open conditions must be verified.
Void protection
Ceiling and raised-floor voids can contain cables and supply or return air. Separate protection depends on fire load, partitions, airflow and the project fire strategy.
Inputs required before design
These inputs turn an application concept into an auditable technical decision.
| Parameter | Why it matters | Design output |
|---|---|---|
| Protection objective and business criticality | Determines room, return-air, cabinet or multi-layer protection. | Protection scope, staged alarms and response plan |
| Plans, sections and cabinet layout | Defines routes, zones, access and cabinet sampling positions. | Candidate holes and detector locations |
| CRAC, CRAH and HVAC modes | Normal, standby and incident modes change smoke movement and dilution. | Room and return-air strategy |
| Hot/cold aisles and rack airflow | Cabinet pressure and exhaust direction affect sampling performance. | Cabinet method and test procedure |
| Temperature, humidity, dust and condensation | Controls filters, moisture management and maintenance intervals. | Environmental accessories and maintenance plan |
| Destination market and applicable rules | Controls approval scope, EN 54-20 class and acceptance documents. | Design basis and compliance file list |
Candidate models
A candidate remains provisional until project inputs and approval scope are reviewed.
CANDIDATE
ASD 531
Individual cabinets or compact equipment rooms.
Review model ↗CANDIDATEASD 532
Medium-sized rooms, return-air sampling or a high-sensitivity single-pipe network.
Review model ↗CANDIDATEASD 535-3 / ASD 535-4
Large rooms, long pipe networks or two independent protection zones.
Review model ↗Questions to resolve
Use these in the first project workshop.
- 01Is the objective room, return-air, cabinet or multi-layer protection?
- 02What detection capability is required when HVAC is stopped or reconfigured?
- 03Which approval, alarm stages and system interfaces apply in the destination market?
Common questions
Why is aspirating smoke detection used in data centres?
High airflow can dilute smoke and carry it rapidly towards return air. ASD places active sampling points in room, return-air or cabinet exhaust locations and supports staged warning, but the system must be designed around real airflow rather than area alone.
Can return-air sampling replace room detection?
Not automatically. Return-air sampling can respond early while HVAC is operating, but shutdown, standby and airflow changes alter its effectiveness. The project fire strategy and local requirements determine whether room or cabinet sampling is also needed.
Which SECURITON ASD model should a data centre use?
ASD 531 can be screened for an individual cabinet or small room, ASD 532 for a medium high-sensitivity single-pipe system, ASD 535-3 for a large single zone, and ASD 535-4 for two independent zones. PipeFlow and airflow verification decide the final model.
Source and review record
Manufacturer facts: SECURITON SecuriSmoke ASD Product Brochure V2.0 EN and current manufacturer design documentation. Application sequence and candidate-model guidance are PEIEN engineering recommendations.
Last reviewed: 27 July 2026. Project values remain assumptions until reviewed by a suitably qualified fire professional or experienced ASD practitioner.
Apply the guidance to your project.
Submit the destination country, application, area, environment, drawings and project stage for a first selection review.