9.4 Electrical Safety, Lockout/Tagout, Fire Safety & Occupational Health
Key Takeaways
- Lockout/tagout under 29 CFR 1910.147 requires each authorized employee to apply their own lock, and only the person who applied a lock may remove it.
- Stored energy must be released or restrained before work begins; in a lift station this includes hydraulic head, capacitors, springs, and compressed air.
- The bloodborne pathogens standard requires the employer to offer hepatitis B vaccination within 10 working days of assignment to employees with occupational exposure.
- Fire extinguisher selection follows the fuel class, and a Class C rating means the agent is non-conductive, not that it is intended for equipment fires alone.
9.4 Electrical Safety, Lockout/Tagout, Fire Safety & Occupational Health
Exam Focus: The Security, Safety, and Administrative Procedures area enumerates safety procedures individually: electrical grounding, hazards, and arc flash; fires; first aid; hazardous materials; infectious diseases/blood borne pathogen protection; lifting; lockout/tagout. Each is separately testable.
Electrical Hazards
Three distinct electrical hazards exist, and they require different protection:
- Shock — current through the body. Prevented by insulation, guarding, grounding, and de-energization.
- Arc flash — the intense radiant and thermal energy of an arcing fault, reaching temperatures several times hotter than the surface of the sun. Prevented by de-energizing and, when work must be done energized, by arc-rated PPE.
- Arc blast — the pressure wave and molten metal shrapnel of the same event.
NFPA 70E governs electrical safe work practices. Key concepts:
- Equipment labeling. Switchgear and MCCs must carry a label giving the available incident energy (in cal/cm²) or the PPE category, and the arc flash boundary.
- Approach boundaries. The limited and restricted approach boundaries govern proximity to exposed energized conductors; the arc flash boundary is the distance at which incident energy would cause a second-degree burn.
- Arc-rated PPE is selected to exceed the calculated incident energy. Ordinary work clothing is not protection — synthetics melt to the skin.
- The de-energized state must be verified. Use the live-dead-live method: prove the tester works on a known live source, test the conductor, then prove the tester still works. A tester that failed between steps would otherwise report a live conductor as dead.
Grounding and bonding provide a low-impedance path so fault current trips the protective device instead of energizing equipment enclosures. Specific requirements for collection work:
- GFCI protection for all portable tools and all temporary power in wet or damp locations — which describes essentially every collection system work site.
- An assured equipment grounding conductor program as the alternative where GFCI is not feasible, requiring documented inspection and continuity testing of cords and tools.
- Portable generator bonding per the manufacturer and the NEC; an improperly bonded generator can energize equipment frames.
- Inspect cords before every use; a damaged cord in standing water at a manhole is a lethal combination.
Operators generally must not open energized enclosures. The rule is to observe, measure where trained and authorized, and report.
Lockout/Tagout (29 CFR 1910.147)
The Control of Hazardous Energy standard prevents equipment from starting while someone is working on it. It applies to servicing and maintenance where unexpected energization or release of stored energy could injure.
The Six Steps
- Prepare — identify every energy source: electrical, hydraulic, pneumatic, mechanical, gravity, chemical, thermal.
- Shut down the equipment by its normal stopping procedure.
- Isolate each energy source at its disconnecting means.
- Apply locks and tags — each authorized employee applies their own personally keyed lock.
- Release stored energy — bleed pressure, block or lower suspended parts, discharge capacitors, relieve springs.
- Verify isolation by attempting to start the equipment (returning the control to off), and by testing for absence of voltage.
The Rules That Get Tested
- One lock per authorized employee. A group lockbox holds the isolation keys and each worker applies a personal lock to the box.
- Only the employee who applied a lock may remove it. The narrow exception for removal by the employer requires a documented procedure, verified absence of the employee, and notification before they return to work.
- A tag alone is not a lock. A tagout-only system is permitted only where a device is not capable of being locked out, and it demands additional safety measures.
- Shift change requires an orderly transfer so protection is continuous.
- Stored energy in a lift station is easy to overlook. Isolating a pump electrically does not address the hydraulic head in the wet well and force main that can drive flow backwards through the pump, nor the weight of a suspended pump on a hoist, nor capacitors in a VFD, which retain a dangerous charge for minutes after disconnection.
Fire Safety
Fire classes and agents:
| Class | Fuel | Typical agent |
|---|---|---|
| A | Wood, paper, cloth, rubber | Water, ABC dry chemical |
| B | Flammable liquids, gases, grease | ABC or BC dry chemical, CO₂, foam |
| C | Energized electrical equipment | ABC or BC dry chemical, CO₂ — must be non-conductive |
| D | Combustible metals | Special dry powder agents only |
| K | Cooking oils and fats | Wet chemical |
A Class C rating means the extinguishing agent is non-conductive, so it can be used safely on equipment that is still energized. Once the equipment is de-energized, the fire is classified by what is actually burning.
Use: stand 6 to 8 feet back with an exit at your back, and apply PASS — Pull the pin, Aim at the base of the fire, Squeeze the handle, Sweep side to side. Fight only small, incipient fires; evacuate anything larger.
Maintenance: monthly visual inspection (pressure gauge in the green, pin and seal intact, nozzle clear, no damage, accessible) and annual professional maintenance, both documented on the tag.
Hot work — welding, cutting, grinding — requires a permit, removal or shielding of combustibles, a fire watch during the work and for a period afterward, and an LEL check where flammable atmospheres are possible.
First Aid and Occupational Health
First aid and CPR. Where no infirmary or clinic is in near proximity, an adequately trained person must be available to render first aid, and supplies must be readily available. AEDs are increasingly standard on collection crews. Because collection work is remote and often two-person, training both crew members is the practical requirement.
Bloodborne pathogens (29 CFR 1910.1030). Raw sewage contains human waste and, frequently, discarded needles. Where occupational exposure exists, the employer must maintain a written exposure control plan, apply universal precautions (treat all sewage-contaminated material as infectious), provide PPE, provide handwashing facilities, use puncture-resistant sharps containers, and offer hepatitis B vaccination at no cost within 10 working days of initial assignment. A post-exposure evaluation and follow-up must be available after any exposure incident.
Other collection-specific exposures. Keep tetanus immunization current given the frequency of cuts in contaminated environments. Leptospirosis is transmitted through rodent urine, which is common in sewers, and enters through broken skin or mucous membranes. Hepatitis A vaccination is recommended for many wastewater workers. The everyday controls are the effective ones: gloves, eye protection, no eating or drinking in the work area, covering cuts before starting, and washing thoroughly before eating and at the end of shift.
Lifting and ergonomics. A cast iron manhole cover weighs roughly 100 to 300 pounds and is the single largest musculoskeletal injury source in the trade. Use a cover lifter, hook, or magnetic lifter with the legs and body positioned so the cover moves horizontally rather than being lifted vertically, and never use the back to break a stuck cover free. For general lifting: assess the load, get help or a mechanical aid for anything awkward or heavy, keep the load close, lift with the legs, and never twist while loaded. Hose reels, pump assemblies, and plate compactors all warrant a team lift or a mechanical aid.
Two operators are servicing a lift station pump. The first applies a personal lock to the disconnect, and the second begins work relying on that lock. What does this practice violate?
An operator electrically isolates and locks out a submersible lift station pump, then begins removing the volute bolts. What hazardous energy source has most likely been overlooked?
Under the OSHA bloodborne pathogens standard, what must an employer provide to a newly assigned collection system operator with occupational exposure to raw sewage?