Purging & Pressurizing Techniques in Hazardous Locations
Published 29 May 2020
Purging & Pressurizing Techniques in hazardous locations.
Purging is a method where a flow of air or inert gas is maintained in an enclosure installed in a classified hazardous area to prevent or reduce the risk of explosive atmosphere occurring.
Pressurizing is a method where the pressure of air or inert gas is maintained at sufficient level inside the enclosure installed in a classified area to prevent the ingress of explosive atmosphere.
There are two main techniques for Purging & Pressurizing:
1) Leakage Compensation
2) Continuous Flow
Using both above techniques will allow an equipment containing electrical components that might be potential ignition sources to be installed in hazardous areas.
Ex-markings for IECEx & ATEX certifications are:
1) Ex pxb (for Hazardous Zone 1)
2) Ex pyb (for Hazardous Zone 1)
3) Ex pzc (For Hazardous Zone 2)
Ex-markings for North American certifications are:
1) Type X (For Hazardous Division 1)
2) Type Y (For Hazardous Division 1)
3) Type Z (For Hazardous Division 2)
References: IEC 60079-2 & NFPA 496
NFPA 496 Standard for Purged and Pressurized Enclosures for Electrical Equipment – this standard provides information on the methods for purging and pressurizing electrical equipment enclosures to prevent ignition of a flammable atmosphere, whether introduced into the enclosure by a surrounding external atmosphere or by an internal source.
NFPA 496
Information Courtesy
Author Behzad Nejad, P. Eng. (Hazcon)
Director & Consulting Engineer at Hazcon Inc.; Hazardous Locations Consulting Services; IECEx, ATEX, CEC & NEC
Specializing in the design, safety and approval of electrical equipment for hazardous locations.Â
Mr. Nejad has over 15 years of experience as an Electrical Engineer and is a sought after professional in the hzardous area and explosion protection industry. He is fully-qualified at the advanced level of all hazardous locations protection techniques including Intrinsic Safety & Non-incendive, Explosion Proof & Flame proof, Increased Safety, Non-arcing, Purging and Pressurization, Encapsulation, Optical Radiation, and Dust-tight enclosures. Mr. Nejad’s tenure in the industry includes six years at the CSA certification agency, working closely with manufacturers (Emerson, GE, ABB, Siemens, Endress-Houser, VEGA etc.) as a technical and certification engineer for Hazardous locations equipment.
The opinions expressed in this article are those of the author.
Hazloc Products with Class 1/Division 2 & ATEX Certifications
EXPERTS IN EQUIPMENT FOR EXPLOSIVE ATMOSPHERES
leaders in ATEX Innovation To The Hazardous Area Industries
Thorne & Derrick are leaders in the development and distribution of Product Innovations that deliver significant improvements to clients plant, people and operational safety in the explosive atmosphere industries.
Your proactive problem solvers experienced in succession planning for the replacement of obsolete, non-conformant and legacy equipment in hazardous areas.
Your first-choice provider of innovative and competitive solutions to ensure ATEX & IECEx Compliance for Hazardous Area Electrical, HVAC & Process Instrumentation Equipment to UK and international projects.
Control Panels | Plugs | Isolators | Enclosures & Junction Boxes | Lighting | Control Stations | Motor Starters | Heat Trace | Gas Detection | Flame Detection | Process Instrumentation | Process Heating | Ventilation Fans | Security Access ControlÂ
Competitive Prices | Extensive Stocks | Technical Support | Express Delivery
