What is Explosion Proof & Intrinsically Safe?
Pseudonym | Vector InfoTech
Electrical system operation in hazardous conditions is tricky. Explosion proof products prevent explosion from penetrating inside, while intrinsically safe products prevent explosion from occurring. Choosing the reliable design for the critical operation is yet more challenging. The crux of the solution is to know the difference between explosion proof and intrinsically safe. Both are complementary to each other and the best selection depends on the application requirements. Flammable sources may be gas, moisture, fire, fog, dust or a metal in contact with the electrical equipment.
To better understand the significance of certified explosion codes, let us start by briefing these terms.
- Products certified XP are explosion proof, which can bear the explosion in the housing and prevent it from entering the device. They are not meant for protection against internal explosion.
- Products certified IS are intrinsically safe, which are rated with a safety barrier to minimise the energy to prevent the explosion. The main intention is to prevent explosion rather than containing it.
Some similarities of both products are long life, minimum maintenance and operation in the explosion prone areas.
Now, let us compare explosion products (XP) and intrinsically safe (IS) products in terms of design, connection, the appropriate use, cost, the zone of operation and certification.
- Connection: XP products require conduits and cables for installation, but there are no wiring requirements for IS.
- Design: XP products contain heavier thick coating than IS products. For such construction, metal or alloy is commonly employed for XP, but polymer or non-metal for IS.
- IS products are designed with inherent safety considerations. For instance, ATEX certified products, mostly IS, require insulation or anti-static components to lessen the explosion effect through internal means.
- High-power operation: XP is preferred over IS since the entire equipment including batteries is controlled such that spark cannot be generated. XP enclosures protect the external environment from harm by causing the travelling gas to cool along the path. Eventually, the electrical components inside the housing will not be exposed to such ignition. Meanwhile, the device can continue the high-power operation without intervention of the spark handled in the outer coating. Contrarily, for normal power conditions, IS is more preferred over XP but it depends on various other criteria such as specifications and reliability.
- Cost: Bulky design, exproof products are more expensive than intrinsically safe products.
- Zone of operation: XP can operate under Zones 0, 1 or 2, while IS is restricted to Zones 1 or 2 only.
- Certification: IS products require rigorous auditing of operation with respect to exproof products. NEC, IEC and ATEX are the compliance bodies predominantly used for hazloc devices and the certification varies per the local requirements. ATEX is specific to IS, while the rest certify both IS and XP.
In conclusion, the best selection of XP and IS depends on the functionality and the area of operation. Having reviewed these distinct features, we certainly come across a flexible solution to the application requirements.