Public Input No. 4-NFPA 496-2014 [ Section No. 5.2.2 ] 5.2.2 Where When the enclosure has been opened or if the protective gas supply has failed to maintain the required positive pressure, the enclosure shall be purged. Editorial change. "Where" is a location, not a situation. The intent is that the enclosure will be purged after (time, not place) it has been opened. Submittal Date: Thu May 15 15:48:11 EDT 2014 Resolution: FR-2-NFPA 496-2014 Statement: Editorial change. "Where" is a location, not a situation. The intent is that the enclosure will be purged after (time, not place) it has been opened.
Public Input No. 6-NFPA 496-2014 [ Section No. 5.2.6.1 ] 5.2.6.1 Components with a free internal volume less than 20 cm 3 (1.22 in. 3 ) shall not be required to be considered as internal compartments requiring protection, provided the total volume of all such components is not a significant portion not more than 10 per cent of the protected enclosure volume. "A significant portion" is unenforceable language, that is not in accordance with 2.2.2.1 of the NFPA Manual of Style, and "significant" is even on of the words in Table 2.2.2.3. AS NFPA 496 must be usable by first parties, second parties and third parties, an objective criterion for acceptance is needed. The Submitter freely admits not knowing if 10 per cent of the internal volume of an enclosure is "significant" enough to warrant protection of individual compartments or not, but 10 per cent gives the technical committee a starting point. The final number chosen may be higher or lower. Submittal Date: Thu May 15 15:59:40 EDT 2014 Resolution: FR-3-NFPA 496-2014 Statement: "A significant portion" is unenforceable language, that is not in accordance with 2.2.2.1 of the NFPA Manual of Style, and "significant" is even on of the words in Table 2.2.2.3. As NFPA 496 must be usable by first parties, second parties and third parties, an objective criterion for acceptance is needed. The committee opted to provide a methodology to evaluate the significant portion by calculation.
Public Input No. 5-NFPA 496-2014 [ Section No. 8.3.5 ] 8.3.5 In applications where flammable mixtures shall be are permitted to be piped into the enclosure through the flammable gas or vapor system, precautions shall be taken to prevent propagation of an explosion back to the process equipment. Editorial change. 8.3.5 does not mandate (shall be permitted) that flammable mixtures be piped into the enclosure, it says what is to be done in the event the mixtures are piped in. "Shall be permitted" not the right term for this provision. Submittal Date: Thu May 15 15:53:03 EDT 2014 Resolution: FR-4-NFPA 496-2014 Statement: Editorial change. 8.3.5 does not mandate (shall be permitted) that flammable mixtures be piped into the enclosure, it says what is to be done in the event the mixtures are piped in. "Shall be permitted" is not the correct term for this provision.
Public Input No. 7-NFPA 496-2014 [ Section No. 9.3.1.2 ] 9.3.1.2 Orifices or other flow-limiting devices shall be located outside and close to within 450 mm (18 in.) of the wall of the building or room. "Close to" is unenforceable language, and not in accordance with 2.2.2.1 of the NFPA Style Manual. Because NFPA 496 is intended for use by first parties, second parties and third parties, an objective criterion for acceptance is needed. The recommended distance of 450 mm is consistent with the placement of conduit seals required by 501.15(A)(2) in the 2014 National Electrical Code. Submittal Date: Thu May 15 16:09:50 EDT 2014 Resolution: FR-5-NFPA 496-2014 Statement: "Close to" is unenforceable language, and not in accordance with 2.2.2.1 of the NFPA Style Manual. Because NFPA 496 is intended for use by first parties, second parties and third parties, an objective criterion for acceptance is needed. The committee identified 10 feet as an appropriate distance to be consistent with the boundary seal requirement of 501.15(A)(4) of the NEC.
Public Input No. 8-NFPA 496-2014 [ New Section after A.3.3.15 ] A.4.3.1. NFPA 496 encompasses enclosures, rooms and buildings. It is not possible to specify acceptance criteria for many different constructions in a single standard. Construction criteria for electrical enclosures may be found in ANSI/UL 50. Construction criteria for pressurized rooms may be found in IEC 60079-13. Structural requirements for analyzer rooms and houses may be found in NFPA 5000. 4.3.1 of NFPA 496 specifies that pressurized enclosures be so constructed as to be unlikely to be damaged under conditions of use. Because NPFA 496 encompasses electrical enclosures, rooms and buildings, there is no single set of criteria available to judge their suitability under this provision. An informative Annex to 4.3.1, and references in Annex B will identify suitable criteria, depending on the type of "enclosure" involved. Submittal Date: Fri May 16 09:41:52 EDT 2014 Resolution: The Committee resolves that the current wording in the standard provides a clear goal and the methods to achieve that is varied such that the committee cannot create a sufficient list of applicable standards. Since the annex was not created in accordance with PI-8 the additional references in PI-9, PI-10, and PI-11 are not required.
Public Input No. 9-NFPA 496-2014 [ New Section after B.1.1 ] NFPA 5000, Building Construction and Safety Code, 2012 Edition As stated in the substantiation for adding A.4.3.1, NFPA 496 needs criteria for judging enclosures, rooms and buildings. NFPA 5000 contains criteria for judging building construction. Submittal Date: Fri May 16 09:55:20 EDT 2014 Resolution: The Committee resolves that the current wording in the standard provides a clear goal and the methods to achieve that is varied such that the committee cannot create a sufficient list of applicable standards. Since the annex was not created in accordance with PI-8 the additional references in PI-9, PI-10, and PI-11 are not required.
Public Input No. 10-NFPA 496-2014 [ New Section after B.1.2.1 ] ANSI/UL 50, Enclosures for Electrical Equipment, Non-Environmental Considerations, 2007, revised 2012. NFPA 496 does not include criteria for judging the suitability of electrical enclosures according to the provisions of 4.3.1. Those criteria are contained in UL 50. Submittal Date: Fri May 16 10:01:23 EDT 2014 Resolution: The Committee resolves that the current wording in the standard provides a clear goal and the methods to achieve that is varied such that the committee cannot create a sufficient list of applicable standards. Since the annex was not created in accordance with PI-8 the additional references in PI-9, PI-10, and PI-11 are not required.
Public Input No. 12-NFPA 496-2014 [ Section No. B.2.1 ] B.2.1 ASTM Publications. ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. ASTM E 659, Standard Test Method for the Autoignition Temperature of Liquid Chemicals, 2005 2014. Update year date of standard. Submitter Full Name: Steve Mawn Organization: ASTM International Submittal Date: Mon Jul 07 12:15:18 EDT 2014 Resolution: FR-7-NFPA 496-2014 Statement: Update year date of standard.
Public Input No. 11-NFPA 496-2014 [ New Section after B.2.2 ] IEC 60079-13-2010, Explosive Atmospheres - Part 13: Equipment protection by pressurized room "p". 4.3.1 of NFPA 496 does not contain criteria for judging pressurized rooms, and objective criteria are needed. They may be found in IEC 60079-13. Submittal Date: Fri May 16 10:44:46 EDT 2014 Resolution: The Committee resolves that the current wording in the standard provides a clear goal and the methods to achieve that is varied such that the committee cannot create a sufficient list of applicable standards. Since the annex was not created in accordance with PI-8 the additional references in PI-9, PI-10, and PI-11 are not required.