SINO Testing Services| 2021-08-27|Return
Sometimes clients come to inquireZhongnuo TestingHe has products that require intrinsic safety certification, what is the difference between this and explosion-proof certification?
This involves the issue of explosion-proof certification for various explosion-proof types.In fact, intrinsic safety is just one type of explosion-proof protection.
Explosion proof certification is the process of determining that equipment meets the requirements of explosion-proof standards, conducting type tests, and conducting routine tests to adapt, and issuing relevant certificates of conformity. The certificate can be specific to Ex equipment or Ex components. The explosion-proof certification here refers to the certification of various electrical and non electrical equipment used in explosive gas and combustible dust environments.
However, there are various types of explosion-proof equipment on the market, including product structures, uses, installation and usage methods, and so onExplosion proof certificationIs the same explosion-proof protection type adopted?
This is definitely not realistic.
We also see lightweight handheld devices in the market, as well as large devices several meters high, which use different types of explosion-proof protection, such as single intrinsically safe, explosion-proof and intrinsically safe, composite explosion-proof (composed of two or more explosion-proof types combined), etc.
At present, the protection types of various explosion-proof equipment on the market mainly include the following:
1. Explosion proof type "d",Put the equipment into an explosion-proof enclosure to achieve explosion-proof purposes. When it explodes, the shell can withstand the explosion pressure without damage. At the same time, the gap between the shell structure can cool the flame, reduce the flame propagation speed, or terminate the acceleration chain, so that the flame or dangerous flame products cannot cross the explosion-proof gap and ignite the external explosive environment, thus achieving the purpose of explosion-proof. Explosion proof standard reference GB3836.2
2. Enhanced safety "e",On electrical equipment structures that do not generate sparks, arcs, or hazardous temperatures during normal operation, measures are taken to reduce or control the working temperature, ensure the reliability of electrical connections, increase insulation effectiveness, and improve the protection level of the casing to reduce the possibility of contamination caused by dirtZhongnuo TestingMeasures such as moisture entry are taken to reduce the possibility of ignition faults and improve the safety and reliability of equipment under normal operation and specified faults (such as motor rotor blockage). Explosion proof standard reference GB3836.3
3. Intrinsically safe type "i",Intrinsically safe explosion-proof type refers to an intrinsically safe circuit in which all circuits inside the equipment are unable to ignite the specified explosive gas environment due to any electrical sparks or thermal effects generated under standard specified conditions (including normal operation and specified fault conditions). Intrinsic safety type starts with limiting the energy in the circuit, reducing the potential spark energy to below the specified ignition energy of the gas mixture through reliable control of circuit parameters, and limiting the surface heating temperature of wires and components to below the specified ignition temperature of the gas mixture. Explosion proof standard reference GB3836.4
4. PositivePressure type "p",Inject fresh air or inert gas at a certain pressure into the casing of the equipment to prevent surrounding combustible gases from entering the interior of the casing, thereby preventing point source ignition from coming into contact with explosive gases and achieving the goal of preventing explosions. Explosion proof standard reference GB3836.5
5. Liquid immersion type "o",Liquid immersion explosion-proof type is to immerse the entire equipment or its components in oil (protective liquid), so as not to ignite explosive gas environments above the oil surface or outside the casing. This is an old explosion-proof technology method mainly used for switchgear. The formed arc and spark are immersed in oil. Explosion proof standard reference GB3836.6
6. Sand filled mold "q",Sand filled explosion-proof type is an electrical equipment protection type that fills the outer shell with sand particles or other specified powder materials, so that under specified usage conditions, the arc or high temperature generated inside the shell cannot ignite the surrounding explosive gas environment. Explosion proof standard reference GB3836.7
7. N-type,Type N is an explosion-proof form of electrical equipment. This type of electrical equipment cannot ignite the surrounding explosive environment during normal operation and under certain conditions specified in this standard (only referring to the light source failure condition of the lamp).
The non spark type originally only referred to electrical equipment that does not generate sparks or arcs during normal operation, such as AC asynchronous motors. Based on this, some safety measures were taken, such as using non spark materials for fan blades, IP44 or IP54 protection level for the casing, and appropriately increasing electrical clearances and creepage distances. Later, this explosion-proof concept expandedZhongnuo TestingFor electrical products that generate sparks during normal operation, measures such as gas sealing, simple ventilation, or energy limitation should be taken according to their situation to achieve a certain level of safety. Due to the expansion of this explosion-proof type, the term "spark free" is no longer very precise and is now often referred to as the "n" type. Explosion proof standard reference GB3836.8
8Pouring and sealing type "m",Seal the parts of the equipment that may generate sparks or high temperatures in a sealing agent (resin) so that they cannot ignite the surrounding explosive mixture. Explosion proof standard reference GB3836.9
The above is a list of explosion-proof protection types for electrical equipment used in explosive gas environments. Intrinsic safety type is only one type of explosion-proof protection type, and intrinsic safety certification is only the protection form adopted in explosion-proof certification.