If you are designing, specifying, installing, or maintaining a refrigeration system to comply with EN 378, you will need to know what is required for gas detection and leak notification. This is important to know for occupied spaces, walk-in freezers / cold rooms and machinery / mechanical equipment rooms to ensure safety and environmental requirements are achieved.

What is EN 378?

Standard EN 378 relates to safety and environmental requirements of refrigerating systems and appliances. EN 378 has four different parts to the standard- each part relating to different stakeholders within the design, manufacture and installation process (Parts 1 to 3). Part 4 focuses on the operation, maintenance, repair and recovery aspect of refrigerating systems. Our guidance outlined here, relates to the specification and deployment of gas detection equipment, to support plant / equipment designers, manufacturers, and installers.

EN 378 Applications

EN 378 compliance outlines different safety requirements based on where refrigeration equipment is deployed (location classifications) and occupancy type. Gas Safety detection equipment alarm sequence is initiated when refrigerant exceeds the practical limit or upon detector failure. EN 378 location classifications and requirements can be summarized as:

Machinery RoomsCold RoomsOccupied Spaces
Gas Detection Required?YesYesYes
Alarm RequirementsAudio Visual Alarms both inside and outside the room (can also include supervised location)Audio Visual Alarms inside the room. Best practice to also include outside the room.Audio Visual Alarms inside the room and supervised location
Notification ResponsesActivate emergency mechanical ventilation countermeasures and alert building management systemsActivate countermeasures and alert building management systemsActivate countermeasures and alert building management systems


Gas Safety Alarm Notifications and Responses

When the concentration of refrigerant exceeds the safety threshold, (which is determined by the refrigerant itself in accordance with EN 378-1: 2016 Annex C), gas safety detectors must activate a notification alarm system. Ammonia (R-717) has specific requirements which you can read about on our Ammonia compliance page.

EN 378 refrigerant detector requirements where A2L, A2, B2L (not NH3), B2, A3, B3 gas categories are used shall activate the alarm signal at a level not exceeding 25 % LEL of the refrigerant. Detectors should continue to activate at higher concentrations. The detector pre-set shall be set lower for the toxicity, if applicable. It shall automatically activate an alarm, start mechanical venting and de-activate the refrigeration system when it triggers.

Alarm systems must warn both visually and audibly to be EN 378 compliant. Depending on the application at your facility as outlined in the table above, different notifications and responses are required. For instance, gas leaks that are above the safety threshold in machinery rooms must activate emergency mechanical ventilation. The alarm should also trigger an alert to a relevant authorized person so that they can take the appropriate responding action.

Gas Detector Requirements

EN 378 (9.3.1. General) states that “any suitable detector” can be used and should provide an electrical signal at the required value to initiate procedures such as valve shut-off, alarm activation, ventilation operation or other necessary safety requirements.

Compliance requirements state that detectors should be ‘continuously monitored for functioning’ meaning that if the detector failed, the emergency procedures should be initiated as if there had been a refrigerant leak event.

Maintenance And Calibration

For maintenance and calibration, EN 378 requires that gas detectors shall have an appropriate maintenance period established (EN378-3:2016, 9.3.1) and be able to be functionally tested (EN 378-3:2016, 9.4). The main maintenance requirement for a gas detector will usually be a periodic calibration, and in some cases a replacement of the sensor element (some have limited lifespan). Much like configuration processes, the calibration of gas detectors has often required interference with circuit boards to make manual adjustments. This can easily be done incorrectly.

Selecting a system where the calibration gas data is entered (ideally by scanning the gas bottle to automatically populate the data) and then all adjustments are made electronically makes this process more user friendly and hard to do incorrectly. Again, leak detectors using a mobile application can make this activity very straightforward.

Bacharach Solutions

Bacharach offers a wide range of industry-leading, leak detection solutions for EN 378 compliance. Gas safety monitoring systems such as the MGS-410, MGS-450, MGS-460 offer low temperature performance down to -40ºF/C.

Integration with BMS / BAS Control SystemModbus, BACnet, LonWork and analog communicationsModbus, Digital and analog communicationsModbus, Digital and analog communications
On-Board AV AlarmsTri-color LED Alarm / Audible NotificationTri-color LED Alarm / Audible NotificationTri-color LED Alarm / Audible Notification
Relays / Alarm Outputs333
Temperature Zone / ApplicationLow and MediumLow and MediumLow and Medium
Sensing MediumElectrochemical (EC), Catalytic Bead (CAT)Electrochemical (EC), Catalytic Bead (CAT)Electrochemical (EC), Catalytic Bead (CAT)
Remote placement of sensors/sample pointsMGS-410 with MGS-402 controller: 1,000m from transmitter5m from transmitter5m from transmitter
Sensor Typical Life SpanUp to 7 yearsUp to 7 yearsUp to 7 years
Maintenance (functional test / calibration)Annual- manual / via Bluetooth™ appAnnual- manual / via Bluetooth™ appAnnual- manual / via Bluetooth™ app
Sensor channels111
User InterfaceMobile app interface with Bluetooth™ connectivityMobile app interface with Bluetooth™ connectivityMobile app interface with Bluetooth™ connectivity