Will Table 130.7 of NFPA be adopted in the CSA Z462?

I hate to be doing everything based on this NFPA Table 130.7 and then find CSA Z462 has not adopted this table.

Would someone please tell me if the Z462 will include table 130.7 as is with no changes? Or if some changes will be done, please tell me what changes are being proposed.

Raffle

CSA Z462 Technically Harmonized with NFPA 70E 2009

Yes this table is retained as are all the tables in the 2009 70E. I am on the CSA Z462 Technical Committee, one of the mandates from NFPA to CSA was that we had to maintain technical harmonization.

Z462 references other existing Canadian Standards as a priority, for example CSA Z460 Control of hazardous energy - Lockout and other methods.

FYI, you can pre-order CSA Z462 on CSA's website right now, should ship and be in your hands by the middle of January.

Regards;
Terry Becker

The CSA Z462-08 standard offers default values in tables that are often used for temporay power or before a software arc-flash hazard analysis has been completed

The tables have to be used with extreme caution as they do not reflect all situations because of the variations in circumstances at each facility i.e. Utility MVA, transformer impedance and fault currents.

In large diversified electrical systems available fault currents can produce dangers beyond the scope of the tables

"An arc-flash hazard analysis should be performed in association with or as a continuation of the short-circuit study and protective-device coordination study."

Software arc-flash hazard analysis to determine incident energy calculations flash hazard boundaries and limits of approach should be calculated to make accurate decisions for live work PPE Equip & PPC Clothing determinations

John Salmon

CSA Z462 Table 4

Just to let you know Table 4 will be reviewed moving into 2009 by the CSA Z462 Technical Committee.

It has limitations as outlined by the Notes and how it was developed.

Regards;
Terry

In CSA Z462,Table 4, all listings cover risks from HRC 0 to HRC 4.No tasking is evaluated at greater than HRC 4.Many of the tasks listed in Table 4 will in fact after risk analysis studies, calculate to be in some cases much higher than those HRCs listed.Prior to completion of risk analysis : Is it considered prudent to accept Table 4 at face value when selecting PPE and/or safe work methods?
Any feedback would be appreciated. Eldon

Eldon:

You cannot use Table 4 unless you comply with the Notes and restrictions that apply.

I see a lot of people making the mistake of using Table 4 as is without applying a Hazard Task Analysis process, which should force you to review the notes and confirm if you can use them based on available fault current and clearing time.

Make sure that you read the table headings for Table 4, the arc rating listed is a minimum value, that said HRC 4 is 40 cal/cm2 or higher.

As well Table 6 is only to be used when you use Table 4, otherwise we should be referring to arc flash protective clothing by its ATPV value and ensure we have an ATPV value that is higher than the assessed incident energy at the assumed working distance.

What is happening is people are using the HRCs to discuss arc flash clothing which is ok at long as you use Table 4. We need to be careful as you may have a 23 cal/cm2 incident energy level, which is HRC 2 as per Table 4, but you only have 8 cal/cm2 HRC 2 clothing.

I hope this makes sense, if not please reply back.

Regards;
Terry Becker
http://www.esps.ca
terry.becker@espsi.ca

Thanks Terry:Since my original post here,I have learned of the qualifier regarding a Hazard Task Analysis regarding the notes in reference to short circuit current and fault clearing times in Table 4.It is my belief that there is no substitute for the Incident Energy figures calculated by a risk analysis study and at that time I believe we like most people in the industry will move away from the HRCs to ensuring that the PPE exceeds the Incident Energy calculations in cal/cm2.
That said,you referred to a 23 cal/cm2 as HRC 2?My interpretation of this would be HRC 3 with a minimum PPE rating of 25 cal/cm2.My understanding is:
HRC 1 - >1.20 cal/cm2-4 cal/cm2 HRC 2-> 4 cal/cm2-8 cal/cm2
HRC 3 ->8 cal/cm2-25 cal/cm2 and HRC 4->25 cal/cm2-40 cal/cm2.I do understand that the PPE for each of these categories must be at minimum the rating of the maximum of the HRC.Am I on track with this Terry? Eldon