Hazardous Area Electrical Protection
Process and plant considerations will often require the installation of electrical systems and instruments in hazardous atmospheres that pose the potential danger for electrical ignition, resulting in fire or explosion. This concern is particularly common in chemical manufacturing, oil and gas refineries, oilfield equipment and services, and other industries where combustible liquids, gases, or vapors are found. Neal Systems has 25+ years of experience helping plants choose a safe and reliable electrical protection solution for their signals, displays, and panels in hazardous areas.
Click below to see our Hazardous Area Electrical Protection solutions for your application need:
- OSHA Standard
- MTL Intrinsic Safety Introduction
- Expo White Paper: Purge & Pressurization Advantages, Methods and Guidelines
- Purge System Applications
- Technical Info Sheets
- Do I Need a Barrier or an Isolator?
- Expo Technologies Innovation for Purging and Pressurization
- Reliability, Availability, Maintenance, Return on Assets and Surge Protection
- Expo Video on Purge and Pressurization Enclosure
Intrinsic Safety Protection
MTL products are used in all types of hazardous locations, from offshore oil and gas platforms, power production plants, and petrochemical installations to pharmaceuticals, telecommunications, and other manufacturing plants. MTL is a recognized world leader in fieldbus power systems and wiring components, intrinsic safety interfaces, and surge protection techniques as well as being a leading authority in industrial Ethernet and HMI / visualization for hazardous locations.
INTRINSIC SAFETY BARRIERS / ISOLATORS
MTL’s barriers passively prevent dangerous electrical signals through the use of a Zener diode to divert excess electrical energy to the ground. Isolators perform a similar function with simplified installation and elimination of ground fluctuation problems.
ALARM BEACONS AND HORNS
MTL offers a range of notification products to keep workers in hazardous areas informed quickly and clearly of any potential hazard. The range includes sounders, beacons, LED clusters, and alarm displays, all certified for use in potentially hazardous areas.
Purge Gas Protection
Purge and pressurization enables you to use any electrical equipment inside an enclosure in a hazardous location. Expo Technologies’ purge systems get your equipment up and running with comparatively quick installation, ready access, and easy maintenance.
|I Gases, vapors, and liquids
B: Hydrogen, etc.
C: Ether, etc.
D: Hydrocarbons, fuels, solvents, etc.
|Normally explosive and hazardous||Not normally present in an explosive concentration (but may accidentally exist)|
|E: Metal dusts (conductive,* and explosive)
F: Carbon dusts (some are conductive,* and all are explosive)
G: Flour, starch, grain, combustible plastic or chemical dust (explosive)
|Ignitable quantities of dust normally are or may be in suspension, or conductive dust may be present||Dust not normally suspended in an ignitable concentration (but may accidentally exist). Dust layers are present.|
|III Fibers and flyings
|Textiles, wood-working, etc. (easily ignitable, but not likely to be explosive)||Handled or used in manufacturing||Stored or handled in storage (exclusive of manufacturing)|
The strength and shape of the enclosure is not as important as full control and knowledge of the circuit design.
The National Electrical Manufacturers Association (NEMA) has developed a rating system to identify the ability of a device or system to afford protection from the outside environment. Factory Mutual (FM) Global and Underwriters Laboratories (UL) have adopted the NEMA Type designations. These rating systems provide information that assists users in making informed product choices in selecting the proper enclosures for hazardous locations. Check these websites:
To see the scope of FM Global’s hazardous location and protection equipment testing and approvals, go here.
FM Global’s Approval Guide contains tens of thousands of products and services tested and FM approved, as well as essential engineering data and technical information. You must first register for access here.
Visit this site for the scope and purchasing of UL 698A, Industrial Control Panels Relating to Hazardous (Classified) Locations.
View this PDF for NEMA Enclosure Types.
For more detailed and complete information, see NEMA Standards Publication 250-2008, Enclosures for Electrical Equipment (100 Volts Maximum).
Type X Purge
Type X reduces the area classification within the purged enclosure from Class I, Division 1, to non-classified where general purpose equipment can be fitted within the enclosure. The enclosure must be purged at least four full volume changes, timed automatically before the electrical interlock supplies power to the general purpose equipment. On loss of pressure the power must be disconnected except under special conditions.
Type Y Purge
Type Y purge reduces the area classification within the purged enclosure from a Class I, Division 1, to Class I, Division 2, where nonincendive (Division 2) equipment can be fitted within the enclosure. The requirements for the operation of the Y Purge are the same as the Z Purge. The difference is the application and contents of the purged enclosure.
Type Z Purge
Type Z purge reduces the area classification within the purged enclosure from Class I, Division 2, to non-classified where general purpose equipment can be fitted within the enclosure. The enclosure must be purged at least four full volume changes before the electrical supply can be applied to the general purpose equipment. This is a manual function completed by the plant operator. On loss of pressure, there is no need to disconnect the electrical supply if the Division 2 area is known to be nonhazardous, but there must be a visual or audible alarm.