The DAX 420 catalytic or infrared Explosive Gas detector is intended for monitoring gas concentration levels in commercial or industrial buildings. The DAX 420 can be used in hazardous areas of explosive atmospheres. It is intended to work with a compatible alarm system and react before the concentration of explosive gas reaches the Lower Explosive Limit (L.E.L.)
The DAX 420 is a catalytic gas detector intended for detecting the presence of explosive gases in ambient air at concentrations of up to 100% of the Lower Explosive Limit. The DAX 420 is also an infrared gas detector, detecting any presence of toxic gas (% vol.). The relationship between the “percentage of the Lower Explosive Limit” (% LEL) and “percentage by volume” (% v/v) varies from one gas to another (see General Standards IEC 60079-20-1).
In an explosive gas detection system, the alarm thresholds should be set in relation to the Lower Explosive Limit for each gas being monitored. Alarm thresholds are typically 20 % of LEL for the first alarm level (A1) and 40 % of LEL for the second level (A2). These thresholds are managed by the control unit. The list of the most important detectable gases are methane CH₄, propane C₃H₈, butane C₄H₁₀, ethanol C₂H₆O, hydrogen H₂ and carbon dioxide CO₂ (this list is not exhaustive).
The DAX 420 comes with explosion proof (d) aluminium metal housing, is dust and water proof (the whole system has an explosion-proof type of protection and an IP6X rating), an Ex-certified metal cable gland, an explosion-proof jacketed sensor head (d), a sintered metal filter and a two-position terminal block for electrical connections. The explosion-proof casing is a stainless steel assembly (base, body and cover) that can be disassembled to allow for the replacement of the sintered metal cell or filter.
The DAX 420 is intended for commercial and industrial buildings. The operating temperature range is from -20°C to +55°C. This product is suitable for use in zone 1 & 2 explosive gas atmospheres and zones 21 & 22 explosive dust atmospheres (see specifications). The DAX 420 detector is ATEX certified and is particularly suitable for industrial applications in explosive atmospheres.
ATEX marking: II 2G Ex db IIC T6 Gb & II 2D Ex tb IIIC T85°C Db
ATEX certificate: FTZU 09 ATEX 0182X
