12.3 Field Safety: Work-Zone Traffic Control, Electrical Hazards, Fall Protection & Hazard Communication

12.3 Field Safety: Work-Zone Traffic Control, Electrical Hazards, Fall Protection & Hazard Communication

Section 12.1 covers chlorine and hydrogen sulfide, and Section 12.2 covers confined spaces, lockout/tagout and trenching. The WPI outlines also list traffic control and work-zone safety, electrical grounding and arc flash, fall protection, fire prevention, first aid, hazardous materials, infectious disease protection, lifting and PPE. These hazards injure more operators than any single chemical.

Temporary Traffic Control

Work on streets and highways follows Part 6 of the Manual on Uniform Traffic Control Devices (MUTCD), the federal standard that Alabama follows. A temporary traffic control zone has four areas:

1. Advance warning area: signs such as ROAD WORK AHEAD tell drivers what is coming.
2. Transition area: tapers of cones or drums move traffic out of its normal path.
3. Activity area: a buffer space (left empty to give errant vehicles room to stop) and the work space where crews and equipment are.
4. Termination area: lets traffic return to its normal path, often with a short downstream taper and an END ROAD WORK sign.

Merging taper length depends on the lateral shift and the speed:

$$L = \frac{W \times S^2}{60} \quad \text{(speeds of 40 mph or less)}$$ $$L = W \times S \quad \text{(speeds of 45 mph or more)}$$

where $L$ is taper length in feet, $W$ is the width of the offset in feet and $S$ is the posted speed (or 85th-percentile speed) in mph. Shifting tapers need at least half of $L$, and shoulder tapers at least one-third of $L$.

Examples. Closing a 12-foot lane on a 35 mph street needs $L = 12 \times 35^2 \div 60 = 245$ feet. Closing a 12-foot lane on a 55 mph highway needs $L = 12 \times 55 = 660$ feet.

Other rules:

• Workers exposed to traffic wear high-visibility safety apparel meeting ANSI/ISEA 107 (Class 2 or Class 3).
• Flaggers must be trained, use a STOP/SLOW paddle, stand where drivers can see them and have an escape route.
• Park trucks so they shield the work area, use rotating or flashing lights, and never turn your back to traffic.
• ADEM accepts up to 4 CEH of temporary traffic control training per renewal period (Section 1.2).

Electrical Safety and Arc Flash

• Treat every circuit as energized until you have verified it is dead. Use lockout/tagout (Section 12.2) and test with a rated meter using the live-dead-live method: check the meter on a known live source, test the circuit, then recheck the meter.
• Arc flash is an explosive release of energy from a fault; it causes severe burns and blast injuries. NFPA 70E sets approach boundaries, requires an arc flash risk assessment, labels on equipment showing hazard information, and arc-rated clothing and PPE for energized work. Only qualified persons may work on or near exposed energized parts.
• Use GFCI protection for portable tools and cords in wet locations, inspect cords before use and keep panel fronts closed and clear (OSHA requires working clearance in front of electrical equipment).
• Never open motor control center buckets or operate disconnects while standing in water or without the proper PPE.

Fall Protection and Ladders

• OSHA requires fall protection at 4 feet in general industry (29 CFR 1910.28) and 6 feet in construction (29 CFR 1926.501).
• Guardrails have a top rail 42 inches (plus or minus 3 inches) above the walking surface and a midrail.
• Fixed ladders taller than 24 feet need a ladder safety system or personal fall arrest; new fixed ladders installed after November 19, 2018 must have one, and all must by November 18, 2036. Climbing water tanks without fall protection is prohibited.
• A personal fall arrest system uses a full-body harness, a connector or self-retracting lifeline and an anchorage able to support 5,000 pounds per worker (or designed with a safety factor of two by a qualified person). Plan rescue before anyone climbs.
• Cover or guard open hatches, wet wells and floor openings.

Hazard Communication

OSHA's Hazard Communication Standard (29 CFR 1910.1200), aligned with the Globally Harmonized System (GHS), requires:

• Labels with product identifier, pictograms, signal word (Danger for the more severe hazards, Warning for less severe), hazard statements, precautionary statements and supplier information.
• Safety Data Sheets (SDS) in a standard 16-section format, kept accessible to workers on every shift.
• Training before workers handle a chemical and whenever a new hazard is introduced.

Many plants also display NFPA 704 diamonds on tanks and doors: blue for health, red for flammability, yellow for instability and white for special hazards such as W (water-reactive) or OX (oxidizer), each rated 0 to 4, with 4 the most severe.

Fire Protection

Use the PASS method: Pull the pin, Aim at the base of the fire, Squeeze the handle, Sweep side to side. Never use water on energized equipment.

Noise, Heat and Biological Hazards

• Noise: OSHA's hearing conservation program begins at an 8-hour time-weighted average of 85 dBA; the permissible exposure limit is 90 dBA. Blower rooms, pump galleries and generators often exceed these levels.
• Heat stress is a serious risk in Alabama summers. Drink water often, take rest breaks in shade, acclimatize new workers gradually, and watch for heat exhaustion (heavy sweating, weakness, nausea) and heat stroke (confusion, hot skin, collapse), which is a medical emergency. OSHA addresses heat under the General Duty Clause while it develops a specific heat rule.
• Biological hazards: wastewater carries bacteria, viruses and parasites. Wear gloves and eye protection, wash hands before eating, drinking or smoking, keep food out of work areas, cover cuts and change out of soiled clothing before going home. Keep tetanus immunization current and follow the utility's medical program.
• Lifting: plan the lift, keep the load close, lift with the legs, avoid twisting and use hoists or a second person for heavy items such as pumps and manhole covers.