How to redue your fleet's greenhouse gas emissions. Smartrak Conversations Episode 05 - Passenger Management. Is a pool vehicle booking solution right for you? Get in touch with Smartrak Fill in the form below and we'll be in touch shortly. Recent Posts. In particular, dust can often be highly combustible. A fire needs fuel, oxygen and an ignition source.
Flammable gasses, vapors and dust provide the fuel, oxygen is present in most environments, and ignition can come from a spark or hot surface. Every fire is dangerous, but in more extreme cases combustion is so rapid as to cause an explosion. OSHA has many reports of devastating fires and explosions across a wide range of industries. Preventing fire and explosions is a top priority as no business or organization wishes to be responsible for causing death and injury.
Additionally, the direct financial penalties of such events — punitive fines and increased insurance premiums— can cripple a previously successful operation. Intrinsic Safety IS is an approach to the design of equipment going into hazardous areas. The idea is to reduce the available energy to a level where it is too low to cause ignition. That means preventing sparks and keeping temperatures low. The alternatives are to design systems so oxygen is excluded by purging with inert gas or to isolate possible sources of ignition.
This can be done either by putting equipment in enclosures strong enough to contain an explosion or by moving it outside the hazardous area. Section and provide definitions of hazardous areas. The reason for the duplication is that is the newer version, structured to harmonize the definitions with those used outside the United States.
Section of the NEC defines Class 1, 2 and 3 locations. Class 1 relates to gases and vapors, Class 2 to dust, and Class 3 to fiber.
Within each Class are two divisions. A Division 1 designation means the hazard can exist under normal conditions or could exist because of maintenance work or because of leakage or breakdown. Division 2 denotes a location where gases or vapors are confined and only escape due to accidental rupture or breakdown, where build-up is prevented through positive ventilation.
Class III locations are those which are hazardous because of the presence of easily ignitable fibers or flyings. Section follows the same principles but uses Zones rather than Classes and Divisions. It cannot store sufficient energy to ignite a flammable gas or vapour and cannot produce a surface temperature high enough to cause ignition.
Almost all portable instruments are certified intrinsically safe. Permanent installations may include intrinsically safe barriers that are located outside the hazardous location. These barriers limit the amount of energy available to the device located in the hazardous area. Our team at Levitt-Safety can help you understand whether your product is intrinsically safe or explosion-proof.
Save my name, email, and website in this browser for the next time I comment. What do intrinsically safe and explosion-proof mean? How are hazardous locations classified?
Divison represents the degree to which the hazard is present in the area. Group represents the type of hazardous material in the area. Hazardous location class Class I: Flammable gases, flammable liquid-produced vapours and combustible liquid-produced vapours. Class II: Combustible dust Class III: Ignitable fibres or flyings Hazardous location division Division 1: Gases or vapours are or can be present at any time in sufficient concentrations for an explosion hazard under normal operating conditions.
Division 2 Gases or vapours are not normally present and are present only in the event of a leak in some kind of containment vessel or piping, again in potentially hazardous concentrations. Group C Atmospheres containing ethyl-ether vapors, ethylene, or cyclopropane. Although there are some subtle differences, engineers and the market in general usually use both terms to mean the same thing, i.
E2S Ltd. The cable must be terminated using Exd certified cable glands and junction boxes. Here safety in hazardous areas is achieved by using a zener barrier situated between the control panel and the device e. The basic I. Although there are few restrictions on the type of cable used in IS circuits all cables have inductance and capacitance, and hence energy storage capabilities, thus they can affect system safety.
The capacitance and inductance values of a given cable should be readily available from the cable manufacturer. In addition the capacitance and inductance values of the field mounted devices such as IS sounders and smoke detectors, must also be taken into account, again the values should be readily available from the manufacturer Consequently the system design imposes restrictions on the amount of each of these parameters.
A great deal has been written on this subject but only rarely is there a serious limitation placed on the available cable. PVC with a minimum insulation thickness of 0.
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