Vehicle Exhaust, Outdoor Environment, Fire Retardant and Work Center Testing Applications
Flexible, portable, high attenuation EM RF shielded environments are in demand for many testing applications. Vehicles of all sizes, can be tested in a RFI / EMI screen rooms with proper intake and exhaust systems. Mobile outdoor RF isolation testing tents can be assembled on-site when needed in isolated areas. Fire retardant liners and systems support local fire code requirements. Work center structures assist semi-conductor manufacturing.
Vehicles from small garden tractors to large aerospace units (Mil-STD 461) can be set up for testing in a modular unit with collapsible sections, removable thresholds and/or custom-sized doors. Select Fabricators has developed a new, removable threshold that eases entry into their patented single door, double magnet system (US Pat. No. 9,029,714) including level grade guides and recommended floor protection mats. The door itself is optionally removable as well as sized for the vehicle. A recent example of this design is a 20’ x 18’ vehicle door to accommodate the object under test.
Shielded intake and exhaust systems have been developed to deal with vehicle emissions. The systems feature large vents with an exhaust waveguide vent pipe. With proper design and preparation, vehicles of all types and designs can be tested in-house or outdoors, see below, in mobile, modular units.
Fire Retardant Measures
Not that it’s ever happened, however, Select Fabricators has customers who must adhere to local fire codes. Whenever using a portable, shielded enclosure for any unit, it is important to check with state codes, the local fire marshal and/or corporate safety officer before beginning the design process. California has codes in place anytime employees are in a structure which must be considered.
In our opinion, the test method for compliance should be NFPA 701-2004: test method 2 for the materials instead of UL 94. The NFPA test method tests the materials, not the completed assembly. The use of UL 94 came from the testing of EMI gaskets which are not the same as a portable screen room.
NFPA 701-2004 “Covers fire safety requirements that apply to flame-resistant materials which are used extensively in the interior furnishing of buildings and transport facilities, in protective clothing for certain occupations and situations, and for protective outdoor coverings such as tarpaulins and tents.” – ANSI – American National Standards Institute
We’ve created designs for customers with fire code requirements:
- SFi uses a liner that is tested and certified by the manufacturer to NFPA 7001-2004. It is used inside the structure as a liner and/or outside as a cover. The shielded enclosure can also be completely encased.
- Fire suppression using the tent’s frame to support plates and couplers for a sprinkler system.
We are also working on projects that meet codes using a few new methods under development. Contact us.
Vehicles and the Outdoors
Sometimes it is important to test vehicles in the environment where they will be used, or for privacy. Select Fabricators worked with our partners to provide an outdoor structure with SFi’s RF shielding enclosure inside. The outside structure is set up first to protect the tent. The outer structure is wind and snow load rated and vented for fresh air, very important when testing a vehicle.
RF shielded work center
In this case, electronic manufacturing equipment needed shielding to make sure production goes smoothly with room for workers to monitor the equipment. Recently we designed an RF / EM shielded enclosure system for a piece of processing equipment that weighed over 2,000 pounds and required an 85” tall opening. The enclosure was specially constructed with a removable threshold and air conditioning to cool the equipment and supervising personnel. The EMI RF shielded tent and frame is truly portable; the disassembled frame and tent fit into rugged plastic cases and can be transported easily between locations when needed.
More than pop-up units for testing consumer devices, Select Fabricators’ RF/EMI tent enclosures are being used for a rapidly increasing number of manufacturing and testing needs. Large or small, each shielding unit can be purposed built to meet the testing standards, code requirements, and manufacturing processes.