Lower Explosive Limit (LEL) Detection: ExSis- Our flammable Gas monitoring system

The ExSis flammable Gas detection unit from Operational is a catalytic (CAT) or infrared (IR) solvent monitoring safety system.

It is a high quality LEL gas monitoring system that uniquely provides a complete answer to the demands of safety standards in an industrial environment.

ExSis machine

  • The intended designs of the Operational LEL systems comply with the requirements of PL d according to
    EN ISO 13849-1 and have been certified by TUV to be used in safety related applications to
    this level, as required by EN1539
  • Systems are modular, compact and can be fitted into any type of duct, oven, dryer or enclosure.

Benefits of ExSis Gas Detection System:

  • Compatible and independently evaluated for use with EN 1539: 2015 PL d safety (equivalent to SIL2).
  • Fast acting IR detector with calibration for life.
  • Duct mounted Catalytic sensors without the need for sample systems.
  • Protected sample line to prevent tampering.
  • Tamper resistant assembly with locked enclosure.
  • Allows internal dryer energy saving with recirculation systems.
  • Allows reduced final exhaust to abatement systems with substantial reduction in the size and capital cost of new abatement systems.
  • Allows improved operating cost due to less exhaust air volume to treat in existing abatement systems with correspondingly higher solvent concentrations and thus fuel values.

Our Products

ExSis – The original ExSis unit is a gas sampling and monitoring safety system that detects percentage LEL levels. It is a modular field mounted unit which can also be panel mounted. Complete with built-in alarms and display, the design is compact and easy to maintain.

ExSis Multi – This panel mounted ExSis control system is the perfect way to replace a traditional rack mounted system. It allows LEL gas monitoring to be integrated into existing manufacturing processes while optimising efficiency and safety. 

Sensor options

IR – Infra-red – The infrared sensor works on the principal of Infra-red absorption of hydrocarbons. It benefits from requiring less maintenance and has short response times. Carbon bonds in the gas absorb a portion of the infra-red light which is compared to a non-absorbed reference to identify the flammable hydrocarbon content of gas.

CAT – Catalytic – The CAT or catalytic sensor detects gas by comparing the resistance between two catalytic beads which are heated to break down the flammable hydrocarbon releasing additional heat. The ‘measurement bead’ measures the heat released which is compared to the other ‘reference bead’.

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Understanding LEL detectors

LEL stands for Lower Explosive Limit. When combustible gases or liquids (solvents) are used in a process, they can form explosive vapours. The  substances have a Lower Explosive Limit which can be found on the Material Safety Data Sheet (MSDS). Operating companies must monitor their gases to ensure they stay within safe operating limits.

LEL Gas Safety Systems, specifically LEL Sensors, monitor, detect and alarm at safe levels within the Lower Explosive Limit of a material. LEL Sensors should be pre-calibrated for the specific substances used to then monitor and alarm for LEL safety.

LEL Sensors work to monitor gas levels in the safe range of the MSDS before the LEL level reaches the set parameters. The LEL monitor will alarm when LEL levels are above the specific processes safe settings.

Operational fit LEL Gas Safety Systems for industries which store or use combustible gases or liquids (or solvents) within their process. LEL gas sensors increase LEL safety and prove compliance with the required levels.

LEL systems are such an important part of the safety process. Therefore, we discuss your requirements beforehand to understand the characteristics of the combustible gas or solvent vapour that the LEL system is required to detect. We can then accurately locate a suitable placement for the correct type of LEL sensor. We also ensure that the correct alarm levels, number of LEL sensors and alarm levels are set to provide complete LEL safety.

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