At 09:17 AM 4/20/99 -0700, you wrote: >Anybody know what it takes to use a 15 year old chamber and whip it into >shape for maximum certification capability (3 m range only)? > >We're talking modular chamber with glued on cones to be dismantled and >reassembled (no doubt all the old cones will be lost) > >Has anyone done this?
I have been involved in a few room and anechoic chamber relocation projects. There are tons of issues with a project like this, I'm just listing a few major ones: a. The size (and manufacturer) of the shielded room. Size and structural strength determine what absorber treatment is possible and, hence, what types of (compliant) tests can be performed. In the case of a modular room it is usually possible to change the room size to accomodate these requirements. b. The condition of the shield and the accessory hardware (filters, lights, etc.). Modular shielding materials are fairly forgiving to relocation provided the dismantling and rebuilding is done with care and under expert supervision. Achieving shielding effectiveness in a used room does not have to be any more difficult than in a new room, provided a number of guidelines are taken into account and the basic materials are in good shape and clean. c. The absorber material. Sometimes cones can be re-used in the new chamber but that depends on the type, the shape they're in and how much is lost during dismantling. It would be smart not to re-use 15 year old absorber materials since foam absorbers do not age very gracefully, unless their use is required because of cost considerations. Generally speaking, this kind of work is not recommended as a do-it-yourself project. As indicated by other replies, dismanting and rebuilding a shielded room takes a lot of effort. A number of independent shielded room installers are out there doing an excellent job of relocating existing shielded rooms for a very competitive price. They can also remove the old cones and install the new absorbers. As far as the anechoic design (the absorber treatment) goes, that is most definately better left to the experts. When we take on a project like this, the absorber design has first priority since this is the most critical factor in a chamber that needs to meet strict anechoic performance criteria. Very few companies have the expertise and tools required to do an anechoic design properly. As far as cost goes, on paper it might seem to be a lot cheaper to relocate an existing chamber than to purchase a new chamber. However, the cost savings are limited by loss of materials during the relocation process as well as the cost of modifications and upgrades which have to be made to the room configuration to meet the requirements of the new test standards and the increased cost of labor. Also, the advantages of building a new chamber are obvious: chamber configuration optimized for your applications, new materials which will last in excess of 15 yrs, warranty, etc. Before anyone takes on a project of this magnitude, it is probably wise to have a project cost estimate and trade-off analysis done. -Robert Robert Bonsen Principal Consultant Orion Scientific email: [email protected] URL: http://www.orionscientific.com phone: (512) 347 7393; FAX: (512) 328 9240 --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
