4.4 Where your job stops, and who does the rest

1 Three decisions, three different people

Almost everything in hazardous locations comes down to one of three decisions, and they belong to different roles for good reasons.

This course has been training for the third row. It gives you enough of the first two to understand what you are protecting and why — which is exactly the amount you need, and no more.

2 "Qualified person" is defined, and it is narrower than a job title

29 CFR 1910.399 defines a qualified person as "one who has received training in and has demonstrated skills and knowledge in the construction and operation of electric equipment and installations and the hazards involved."

Note 1 to that definition is the part worth memorizing: "Whether an employee is considered to be a 'qualified person' will depend upon various circumstances in the workplace. For example, it is possible and, in fact, likely for an individual to be considered 'qualified' with regard to certain equipment in the workplace, but 'unqualified' as to other equipment."

Qualification attaches to the equipment, not to the person's trade or seniority. A first-class electrician with twenty years on switchgear may be entirely unqualified on an intrinsically safe loop or a purge system, and the standard anticipates precisely that. Two words in the definition do the work: demonstrated skills. Having read about something — including having completed this course — is not demonstration.

3 When you find something that does not match

You will. Everyone who learns this material starts seeing it — a general-purpose fitting in a classified room, an unpoured seal, a cover with four bolts of six, a nameplate that says nothing at all. The temptation is to fix it on the spot, and that is usually the wrong move: a well-intentioned field repair to a classified installation can end up in a worse state than the finding, and it erases the evidence that the system was drifting.

1. 1
   Stop and consider whether the condition is immediately dangerous — energized and open, an active leak, a live ignition source in a place that smells of solvent. If it is, control the area first and get people out of it.
2. 2
   Do not improvise. Do not fabricate a plug, torque a cover onto a damaged face, or fill a seal with something from the shop.
3. 3
   Record it: photograph the equipment and the nameplate, note the exact location, and write what you saw rather than what you concluded.
4. 4
   Tag it so the next person sees it, and report it through the route your site actually reads — a work order, a defect log, a supervisor, an engineer.
5. 5
   Ask for the classification drawing for that area. Half of these findings turn out to be equipment in the wrong place; the other half turn out to be a drawing nobody has updated.
6. 6
   Follow it up. A finding raised and never closed is the same as a finding never raised, and it is the one thing an inspector can see in your own records.

4 Five questions before you work in a classified area

If you keep nothing else from this course, keep these. They take two minutes and they cover most of what goes wrong.

5 What this course did not cover

Being explicit about this is part of the training, not an apology for it. The following are real parts of the subject, and none of them is in these sixteen chapters:

• How to classify an area. The methods, the release-source analysis, the ventilation calculations and the distances are in API RP 500 and RP 505, NFPA 497 and NFPA 499, and IEC 60079-10 — all paid consensus standards, and all used by engineers rather than technicians.
• The group and temperature tables. They are in NFPA 70, they are revised, and a copy on a free website is a liability rather than a resource.
• Wiring methods and installation detail — permitted cable types, sealing distances and fill, glands, flexible connections, drainage, grounding and bonding in classified areas. OSHA's own note to 1910.307(c)(3) lists the astonishing range NFPA 70 covers here.
• Purge and pressurization system design — the classes of pressurization, the purge volumes, the interlocks and the alarms.
• Dust hazard analysis as a discipline: testing dusts for explosibility, sizing explosion venting, isolation and suppression.
• Intrinsic safety loop calculations — entity parameters, cable capacitance and inductance, and the control drawings that make a loop legitimate.

If your work is heading toward any of those, that is the point at which this course has done its job: it has told you what you are looking at and given you the vocabulary to ask for the right help.

6 Where to go from here

Three neighboring subjects carry most of the same work, and all three are free on this site. Electrical safety awareness covers shock, arc and the deenergized-first rule of 1910.333(a)(1) — the hazards that are present in a classified area even when nothing is flammable. Lockout/tagout fundamentals covers the energy control procedures that most classified-area maintenance runs under. And HazCom and GHS covers the safety data sheet, which is where the flashpoint, the flammable limits and the ignition temperature of your own materials actually live.

Then the part exam. It is twenty questions across all four parts, it flags the safety-critical ones in the review, and nothing is issued for passing it — no card, no certificate, no credential. What you get is a clear picture of which part you should read again.

7 The vocabulary, in one place

Sixteen chapters produce a lot of terms. These are the ones that come up in a real conversation with an engineer, a supplier or an inspector, with the source of each definition.