Explosion-proof Structure Symbol (ExiaIIBT4) (1) Groups of explosion-proof equipment Explosion-proof equipment is classified into two groups depending on the place where electric equipment is used. Group I: Electric equipment which is used in a dangerous environment within a tunnel or mine Group II: Electric equipment which is used in a dangerous environment within a factory or office. SMC valve belongs to Group II. (2) Classification of gas Classification of gas corresponds to the explosion class of gas specified in the conventional standard, and there are three classes, A, B, and C, depending on the characteristics of explosive gas. The classification of gas specifies the dangerous degree as C>B>A. SMC valve is applicable to the gases classified into A and B. (3) Temperature class Temperature class corresponds to the ignition degree of gas specified in the conventional standard, and there are six classes, T1 to T6. T1 is the least dangerous gas which has the highest ignition temperature, and T6 is the most dangerous gas which has the lowest ignition temperature. SMC valve is applicable to T1 to T4 temperature classes. Symbols Specified by Technical Standard ia Type of explosion-proof structure: Intrinsically safe explosion-proof structure (system) Ex A symbol of the explosion-proof structure based on Technical Standard (rev.) Group: II Classification of gas: Gas of A and B Temperature classification: Gas of T1 to T4 T4 Reference Series 51-SY5000/7000/9000 Specific Product Precautions 6 Be sure to read before handling. Refer to back pages 1 and 2 for Safety Instructions, “Handling Precautions for SMC Products” (M-E03-3) for 3/4/5 Port Solenoid Valves Precautions. Back page 8