1 April 2002
Safety committee in tune with national standards
By Ellen Fussell
Continuing its effort to harmonize U.S. standards with the International Electrotechnical Commission’s (IEC’s) 60079 series, ISA’s SP12 committee spent a good chunk of time at its winter meeting focusing on shock and fire hazard protection. The committee, Electrical Equipment in Hazardous Locations, is defining deviations between U.S. installation codes and those requirements listed in the comparable IEC 60079 series of standards.
"The IEC 60079 series standards do not include requirements for shock and fire hazard protection; the focus is entirely on explosion hazards," said SP12 committee chairman Ted Schnaare. "In the U.S., our standards require all electrical equipment to meet requirements for shock and fire hazards."
Harmonizing U.S. standards with IEC’s 60079 series has been a continuous goal for the committee—influencing the IEC standards as much as possible to prepare them for use in the U.S. "We’re dealing with a number of standards in the series: general requirements, flameproof equipment [types d, e, m, and others]," Schnaare said.
Underwriters Laboratories (UL) is continuing to work with the committee to harmonize its 2279 standard with ISA’s SP12 series of standards. UL 2279 is also a U.S. national standard for hazardous locations, based on the IEC 60079 series. Schnaare said that because both are U.S. national standards on the same topic, "we’re working on aligning these two standards so we’ll have a single U.S. version of the IEC standard. He added the two are very close to meeting their goal, with a "few minor issues outstanding."
Schnaare said a compelling reason for harmonizing the two is to allow the U.S. to participate in the IEC Ex Scheme (see related story below). One of the first requirements, he said, is to identify the U.S. version of the applicable standard and its differences from the base IEC standard.
This task will fall under a UL/ISA correlating committee (formed in October with five UL members and five ISA members). Once the members reach harmonization, this group will keep them in sync if revisions should occur.
"Even though there are two separate organizations promulgating changes, any changes UL suggests will be shared with the SP12 committee through the correlating committee, and vice versa. So in the end, the standards are allowed to change, but they change in lockstep," Schnaare said.
The individual ISA and UL standards development and maintenance processes will go on as they do today based on ANSI requirements. But the communications process through the correlating committee will allow the standards to stay harmonized, Schnaare said.
Another important topic discussed was portable electronic products in hazardous locations (ISA Draft RP12.12.03, Portable Electronic Products Suitable for Use in Class I and II, Division 2, Class I, Zone 2, and Class III, Division 1 and 2, Hazardous (Classified) Locations). "That’s the whole debate about using a cell phone, watch, or insulin pump in Division 2 or Zone 2 classified areas," Schnaare said. "We had a pretty big turnout of people interested in the progress of that document." (See related Safety article in March 2002 InTech).
New projects included discussion on national pipe taper (NPT) threads—the type of threads typically used for explosionproof installations in the U.S. and elsewhere.
"There’s a need out there to harmonize the way we view NPT threads in the U.S. and the way they’re used in the rest of the world, specifically in the CENELEC standards and the IEC standards," Schnaare said. "The main issue is that if you use just the standard specification for the threads, you don’t get the required minimum engagement that you need for explosionproof protection. So we’ve been working on harmonizing those requirements."
The committee plans to have proposals to improve existing NPT standards by its next meeting in October.IT
IEC Ex Scheme
The IEC Ex Scheme is a plan to facilitate international trade in electrical equipment for use in explosive atmospheres. The ultimate goal is to give participating countries’ manufacturers the means to get certificates of conformity confirming that their equipment passes IEC standards and is accepted at a national level. It will also eliminate the need for countries to obtain multiple national certification of equipment for each country in which they want to see their equipment. With an Ex Scheme certification, manufacturers will affix the IEC Ex Mark of Conformity to equipment that complies with the national standard.