The gas mixture in IEC60079-11 that uses oxygen is an option. You are still able to use the 21 +/- 2% that is quoted in 10.1.2 of the standard. The 30% H2, 53% Air, 17% N2 is to allow you to put the safety factor on the gas mixture instead of putting it on either the voltage or current. The ignition during the calibration is more violent because of this.
Best regards Nicholas Ludlam Factory Mutual Research Tel: (781) 255 4847 Fax: (781) 762 9375 http://www.fmglobal.com -----Original Message----- From: DVVENTL Lizette de Vries-Vente [mailto:[email protected]] Sent: Thursday, November 18, 1999 7:50 AM To: [email protected] Subject: IEC 60079-11:1999 Hi Members In the latest edition of IEC 79-11 (Intrinsic safety) the gas mixtures were changed from the 1991 edition to use only hydrogen and air or Oxygen in the mixture. Has anybody started to use this method and do you also experience a more "violent" explosion during the calibration of the spark test compared to the 1991 edition of the gas mixtures ? Thanks for the input, Lizette de Vries-Venter ELECTRONIC ENGINEER Department: Explosion Prevention Technology SABS Tel : +27 12 428 6990 Fax: +27 12 428 6854 Email : [email protected] --------- 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). --------- 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).
