Understanding EN 54-20 Aspirating Smoke Detection Sensitivity Classes

Aspiraiting Smoke Detection Class Sensitivity Table

EN 54-20 specifies 3 classes of sensitivity to help with the vast amount of applications aspirating smoke detection can be used for. This is to ensure that the most appropriate sensitivity aspirating smoke detector will be selected for the proposed application/area.

Server Room

Class A – Very High Sensitivity

For the earliest indication of smoke so that early measures can be initiated before any significant damage is incurred in areas containing high value, critical or strategically important artefacts or operations such as data centres.

Class B – Enhanced Sensitivity

Enhanced sensitivity for effective early detection in challenging environments or within critical equipment e.g. to combat smoke dilution where there are high air flow or where the ceiling is higher than normal.

Class C – Normal Sensitivity

As an alternative to point or beam type smoke detectors (normal sensitivity) for a variety of physical reasons e.g. maintenance access, building deflection, dilution of smoke, and obstructions to line of sight such as cold stores and warehouse facilities.

Eurofyre are the technical suppliers for the extensive range Xtralis ICAM aspirating smoke detection products. Many of which can be configured to class A, B and C sensitivity. Below are a few examples from the large bore ASD category.

EF-FT1 Aspiraiting Smoke Detector

EF-FT1 – High Sensitivity Aspirating Smoke Detector

  • Class A – 16 Holes / 0.04% obs/m
  • Class B – 72 Holes / 0.04% obs/m
  • Class C – 72 Holes / 0.10% obs/m
EF-FTP Aspiraiting Smoke Detector

EF-FTP – High Sensitivity Aspirating Smoke Detector

  • Class A – 12 Holes / 0.04% obs/m
  • Class B – 36 Holes / 0.04% obs/m
  • Class C – 36 Holes / 0.10% obs/m
EF-LASD Aspiraiting Smoke Detector

EF-LASD – High Sensitivity Aspirating Smoke Detector

  • Class A – 3 Holes
  • Class B – 6 Holes
  • Class C – 18 Holes
Xtralis XCC Aspiraiting Smoke Detector

Xtralis XCC – Class C Aspirating Smoke Detector

  • Class C – 18 Holes