Guidelines for the measurement of toxic gases

The Association of Swiss Installers of Security Systems (SES) has established the following guidelines:

For the monitoring of toxic (poisonous) gases and oxygen, such as Ammonia NH₃, Carbon Dioxide CO₂, Chlorine Gas Cl₂ and Bromine Br₂, the following points should be observed:

Number of gas sensors

At least two gas sensors must always be used in each room
For monitoring a room; the maximum monitoring area per gas sensor is 60 m²
In the case of object or area monitoring; the gas sensors must be mounted directly next to the possible gas leak point.

Installation of gas sensors

For gases with a density lower than air, the gas sensors must be mounted on the ceiling. For example: ammonia
For gases with a density greater than air, the gas sensors must be mounted 30 cm above the floor. For example: bromine, chlorine dioxide, bromine, etc.
Special clarifications are required for certain gases and applications. If in doubt, please contact us.

Installation of the gas control panel

A gas control panel should always be installed outside of the danger area.
A gas control panel should be in an easily accessible location.

Power outage

A gas control panel for toxic gases and oxygen must be backed up by a UPS.
The emergency power supply (UPS) for gas warning systems must ensure operation for at least 6 hours.

Servicing the gas warning system

Gas warning systems must be put into operation by the installer.
The gas measuring cells in the gas sensors are wearing parts and must be replaced every 1-5 years, depending on the type of gas.
A gas warning system must be checked and calibrated by the installer at least once a year. Depending on the application, shorter intervals may be necessary.
When servicing a gas warning system, the gas measuring cells must be replaced in accordance with the maintenance plan.