Businesses that operate in hazardous settings need to uphold the utmost safety to prevent accidents and secure employees. Getting intrinsically safe or Explosion Proof Electrical Equipment is crucial. Explosion proof and intrinsically safe (IS) are two classes of lighting based on different ways to prevent explosions.
Difference Between IS And Explosion Proof Equipment
Intrinsically safe devices are also considered explosion proof though they work differently. Explosion proof equipment works on the principle of containing the explosion. That means that the ignition is allowed but contained and prevented from spreading.
Intrinsically safe equipment is designed to prevent the ignition from occurring in the first place. It controls the source of the ignition and never allows it to reach energy levels to cause an ignition.
Features Of Intrinsically Safe Lighting
Intrinsically Safe Lighting usually consists of low-powered lighting that uses batteries, which may be rechargeable. Low-voltage bulbs like LEDs are often used though high-intensity discharge (HID) lights and halogen flashlights may be classified as such.
IS lights are designed to ensure that the amount of electrical energy remains under non-incendive levels. This prevents sparks from occurring at amperages or voltges that could cause explosions in the wrong setting.
A heat sensor is usually incorporated into the IS lighting circuit in industrial settings. This limits the energy input based on the temperature. Ambient temperature controls the lighting that is still required to meet high lighting standards.
HID lamps consist of a transparent, sealed fused quartz tube or fused aluminum tube that contains gas and metal salts. An electric arc starts in the gas, heats and evaporates the metallic salts, and forms a plasma that increases the intensity of the light started by the arc. Most of the energy is used in producing visible light rather than infra-red rays and heat. The light per unit of power is more visible in HID lights than fluorescent or incandescent.
The issue with an HID light is that it uses up the metallic crystals, causing light levels to drop by seventy percent after over 10000 hours of usage.
Features Of Explosion Proof Lighting
The term explosion proof does not imply that the device will survive an explosion, merely that it will prevent one. An explosion proof light is contained in an enclosure that prevents internal sparks from causing explosions, like when gases enter the enclosure.
The enclosure is usually made out of stainless steel or cast aluminum. The lighting is insulated such that in case of an internal explosion, the external surface temperature does not reach the ignition temperature of the gasses in the atmosphere. Durable lenses are used to prevent cracks to prevent leaks and withstand hard working conditions.
Why Intrinsically Safe Lights Are Superior?
- Explosion proof lights are riskier because they allow the explosion to occur and contain it. Disasters could occur if any imperfections in the device are overlooked.
- Intrinsically safe lights don’t allow explosions to occur even in faulty conditions like broken wires or outdated circuit boards.
- It’s simpler to wire intrinsically safe light fixtures because they just need to be wired according to electrical codes.
- Wiring of an explosion proof light fixture is more expensive because of the conduit, enclosure and seal. It also needs heavy-duty housing.
- You need to be vigilant with maintenance checks for damage or leaks in the housing of explosion proof lights.
- Stringent maintenance routine is not necessary for intrinsically safe light fixtures because no fire hazard is involved.
- Intrinsically safe devices include many portable or hand moveable sources of lighting that operate on rechargeable batteries that may be connected to low voltage AC.
Relevant Standards
Several international safety standards certify a light system as intrinsically safe. The International Electrotechnical Commission (IEC) is mainly responsible for developing intrinsic protection standards across the globe though other agencies may develop their own standards. In the US, the National Electric Code (NEC) is usually followed.
Other organizations like FM Approvals issue certifications for products that meet their standards. The Underwriters Laboratories issues certifications for explosion proof or dust-ignition proof equipment in hazardous environments based on thor UL 1203 standards.
