The National Electrical Manufacturers Association or NEMA for short has established a range of standards for electrical equipment enclosures. For more detailed and complete information, NEMA Standards Publication 250. You can reach the National Electrical Manufacturers Association at: http://www.nema.org/

Here is a partial list of the NEMA standards that some of Valley plastic's TM products adhere to:

1. The basic model is both Nema 12 and NEMA 4 compliant  so it can be used indoors and outdoors. To make it Type 4 the enclosures need the covers and baffles for the exhaust holes as shown in the chemical ruggedized unit. They are intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose-directed water; and to be undamaged by the formation of ice on the enclosure

2 .The basic model is NEMA 12compliant  - Type 12 enclosures are intended for indoor use primarily to provide a degree of protection against circulating dust, falling dirt, and dripping noncorrosive liquids.

3.  Nema 12 enclosures  are not intended to provide protection against such conditions as internal condensation 

COMPARISON BETWEEN NEMA ENCLOSURE TYPE NUMBERS AND IEC ENCLOSURE CLASSIFICATION DESIGNATIONS

A.  What NEMA rating does a Valley Plastics™ Computer Cover Have ?

A  Valley Plastics™ computer cover, patent pending, meets the Nema 12 and can be modified as shown in our advanced chemical ruggedized cabinet to meet the Nema 4 standards. The dust, not necessarily the temperature can be of most concern in industrial and home office environments.

Some installations have toxic particles in the air such as sulfur, which combines with the delicate copper traces on the computer cards. In time, those copper traces will pulverize causing a failure or even worse, a highly intermittent and difficult to diagnose fault. Even non-toxic dust, over time will create a film on the computer chips, virtually insulating the components from the benefits of airflow

What is intrinsically safe?

Intrinsic safety is a protection concept deployed in sensitive and potentially explosive atmospheres. Intrinsic safety relies on the equipment being designed so that it is unable to release sufficient energy, by either thermal or electrical means, to cause an ignition of a flammable gas.

Intrinsically safe is achieved by limiting the amount of power available to the electrical equipment in the hazardous area to a level below that which will ignite the gases.

B. Is a Valley plastics™Computer cabinet intrinsically safe?

  Yes, the chemical ruggedized version is in 2 ways. 

 1. Valley™ cabinets, Patent Pending can be fully lined with the Kevlar and carbon fiber and with the polycarbonate Lexan Door window which even GE uses on  their  Roughneck Monitors for oil wells and hazardous areas. Therefore, it is intrinsically as it is comprised of the same plastic cover materials , GE products go into some of the most demanding environments.

2. In addition to those apparatus for making the computer inside the cabinet intrinsically safe the computer itself has intrinsically safe electronics. This provides significant cost savings in maintenance of the equipment in a Hazardous area in combination with the Valley Tm PC Computer covers. The basic design of a compouter's own intrinsic safety barrier uses Zener Diodes to limit voltage, resistors to limit current and a fuse.  Most computers alreay have this feature and that is one of the main reasons the exterior dust enclosures are themselves intrinsically safe. The  PC dust enclosures run a continuous single AC fan so it is very simple, effective and safe. 

Features of Valley Pc Computer Enclosure:

• NEMA 4X Fully Enclosed Automatic Purged Workstation
  • Class 1 Division 1 Compliant
  • Water Proof
  • Dust Proof
  • Corrosion Resistant system.

Topics:

·         Airtight
A sophisticated closed-loop thermal management system utilizes a Coanda injector and axial tube fan to keep internal operating temperatures low. Thompson Industries rugged Valley Plastic ™ industrial Purged series operator interface systems allow for the placement of totally enclosed hardened computers into areas classified as hazardous. Intrinsically safe, this purging (pressurization) approach ensures that there will always be a continuous clean air-flow out of the enclosure thereby preventing the intrusion of explosive gasses or dust into the enclosure. Shock and vibration isolation is provided at two levels -- on the chassis and in the drive bay -- for protection in severe vibration environments.

·         Guarded
 

·         Reliable
The Valley™ industrial purge protected workstation computer cover operates smoothly and efficiently in conditions where other computers would fail. Not merely an enclosure for any type of PC, its electronics and chassis were designed in tandem to provide a reliable and effective solution for harsh environments.

·         The Valley™ industrial plastic computer case utilizes top quality components from DuPont, GE, Plaskolite, Rohm and Haus, and 3M and other industry leaders in our traditional plastics family contacts. Each system is thoroughly inspected and tested before shipping to ensure trouble-free, long-term operation.

·         Flexible
The Valley™ has an open architecture, with the hinged and sliding access doors allowing easy maintenance and upgrades.
 Valley Plastic™ configuration choices range from standard PC options to outdoor service and extreme temperature kits.

·         The size and location of customized conduit fitting to meet specific connection and field installation requirements can be retrofitted to the cabinets.

·         The Valley Plastic ™  purge protected workstation protects servers running valuable and critical Windows-based products, common industrial software, and a wide variety of other third-party products, enabling you to install, utilize, maintain the Valley™  cabinet and safely run the business applications you already know and use with lower maintenance and depreciation costs.