Solution Summary: Using Non-conductive Ladders
Non-conductive ladder is a work practice that can guard workers against electrocution in a case that the ladder contacts the overhead powerline during the process of raising, lowering, moving, or repositioning them.
Ladders used on construction sites to access overhead work are convenient and portable and can be used anywhere at the job site. Because ladders are common equipment, workers overlook the hazards associated with using them improperly or transporting them around the site. Workers may not realize that cranes are not the only equipment that reach powerlines; working with a ladder near a power line also poses the risk of electrocution.
Ladders are effective tools for cleaning, painting, roofing, etc., but sometimes the work zone is close to energized lines, posing the risk of electrocution while working on a ladder. A study by the Consumer Product Safety Commission (CPSC) on ladder electrocution indicated that in 8 years, 54 ladder-related fatalities involved use of metal ladders. Using dry non-conductive ladders can eliminate much of this risk. Different mandatory OSHA standards and voluntary guidelines apply to the use of non-conductive ladders. 29 CFR 1926.450(a)(11), 1926(c)(1), NIOSH[1985b], and AFOSH Std 127-3, ANSI A14.5. Where feasible, ladder use should be minimized by using safer alternatives such as aerial lifts, scaffolds, and platforms. These alternatives primarily reduce fall hazards, so precautions to prevent electrocutions must still be in place. Ladders are appropriately used for access to the work area, working from a ladder or using it as a work platform increases exposure to risk.
IMPORTANT: While using a non-conductive ladder, a horizontal safe zone from overhead live lines should be maintained (Figure 1).
IMPORTANT: Proper ladder setup should be utilized all the time. It is a safe practice to secure the ladders for accidental movements (e.g. secure the extension ladder on top and bottom).
Figure 1. Horizontal safe zone from overhead power lines while working on a ladder (Source: http://www.elcosh.org/)
To guard against electrocution from ladder/power line contact, OSHA regulations prohibit the use of conductive ladders near energized lines.
Wood ladders are the oldest recorded type of ladder. Because wood is an electrical insulator was often less expensive, wood ladders were a good alternative to other types and were historically the preferred choice of homeowners and small shop owners. Wood tends to age relatively fast and can lose its structural integrity over the years, so wood varnishes often are used to extend the lifetime of a ladder. It is important, however, for workers near electric power lines to avoid using ladders contaminated with an oil coating, as this can conduct electricity. Wood ladders coated with a clear varnish finish and washed with soap when necessary to remove surface oil will help it remain non-conductive.
IMPORTANT: Water is also an excellent conductor, so no matter what the ladder is made of, wet ladders should be kept away from the powerlines.
Figure 2. Using wooden ladders for high voltage lines operations
Fiberglass is a prefabricated, manufactured material that is considered an excellent electrical insulator. Ladders made of fiberglass are very durable and have a long life span. Fiberglass ladders can lose their electrical insulation advantage if they become wet. So, it is important to not work near electric lines in rain or any other situations in which the ladder may get wet. Fiberglass ladders weigh less than wood and are easy to lift and move. Fiberglass ladders are the safest choice available for workers working near energized lines.
Figure 3. Fiberglass ladders (Source: http://www.megagroup.enic.pk/)
NOTE: Wood ladders are heavier than other types of ladders, and have higher risk of improper installation due to their weight. Moreover, wood ladders are combustible, which does not make it a suitable solution for construction environment. However, fiberglass ladders are the safest choice available for workers working near energized lines.
Contact with electric current is a major cause of injury and death among construction workers (Janicak 2008). In 2012, the Census of Fatal Occupational Injuries (CFOI) data produced by the Bureau of Labor Statistics (BLS) indicated that contact with electric current was the fourth leading cause of work related deaths—after falls, transportation incidents, and contact with objects and equipment (BLS 2012). Electricity can cause electric burns, electrocution, shock, arc flash/ blast, fires and explosions. One of the major causes of electrocution hazards is contact with overhead power lines and energized sources. Overhead power lines are considerably hazardous since they carry high-voltage electricity. Although electrocution is considered the main risk, other important hazards of working near or on high voltage lines include electrical shock, burns and falls to lower levels. These types of hazards happen when the body become part of the electric circuit, whether by direct contact with an energized source or contact with a conductive material that has become energized. The severity of the electrical hazard depends on several factors, including the length of exposure time, energy deposited into the body, the pathway through the body, wetness or dryness of surface and the amount of current. Because overhead power lines are especially dangerous and carry extremely high voltage, many workers are killed or seriously injured when they come in contact with live overhead power lines.
Therefore, energized overhead power lines at job sites may constitute a significant safety hazard. Previous studies have shown that when metal ladders contact live lines during the process of raising, lowering, moving, or repositioning them, electrocution or shock – and thereby falls to lower levels – can occur. Moreover, wind and uneven ground may cause the ladder to shift and bring line workers into contact with energized lines, causing serious injuries or death.
How Risks are Reduced:
A non-conductive ladder should be used in conjunction with administrative guidelines when workers are working on or near energized power lines. Non-conductive ladders guard workers against electrocution and falls. Therefore, if the worker contacts the overhead powerline while moving the ladder, the non-conductive ladder will not allow the electrical current in the powerlines to reach the worker.
Effects on Productivity:
Using non-conductive ladders at a safe distance can improve productivity by reducing the number of injuries associated with electrocution while working on overhead power lines. Moreover, there is less need to spend time and money to contact a utility company to de-energize lines and then follow all grounding processes to ensure de-energizing (it should be noted that de-energizing is the safest route for working around electrical equipment/lines). In addition, the Fiberglass ladders are light weight and easier/faster to move. Generally, when workers feel safe working on live lines, they will be more productive.
- Make sure the ladder is clean and dry.
- Carefully check power line locations before using or shifting the ladder.
- Lower the ladder when moving it, to avoid make contact with live lines.
- Never work on windy days, since wind can move the ladder and put line workers at risk.
- Place the ladder on a solid surface before using. Tie off the ladder to prevent it from moving, if possible.
- Never touch any type of ladder, even a fiberglass one, if it contacts a live power line.
- If the minimum safety distance cannot be kept, contact the utility company to de-energize lines.
Maintenance and testing:
- All types of ladders must be inspected before and after each use.
- Fiberglass ladders must be kept away from sources of heat and moisture and must be stored in well-ventilated areas.
- Fiberglass ladders should be waxed with paste wax for extended life span.
- If fiberglass ladders are stored horizontally, they should be supported at several points to avoid slipping.
- Fiberglass ladders must be kept clean using soap and water.
- Fiberglass ladders are not malleable. Although nicks and scratches are very common, if there is any doubt, the ladder must be tested before its next usage.
- Wood ladders must be kept clean using soap and water.
- If the varnished surface of a wood ladder becomes scratched, it must be inspected and repaired immediately in order to preserve the wood and to maintain non-conductive features.
- Inspect and use scaffolds and ladders
- Install and maintain temporary wiring systems on construction sites
- Install and repair high voltage lines, transformers and switches
- Install interior wiring systems
- Work with or remove old wiring
To obtain information, visit http://tricamindustries.com/ or contact 1-800-867-7673
To obtain information, visit https://www.louisvilleladder.com/ or contact 1-800-666-2811
Little Giant Ladder Systems
To obtain information, visit https://www.littlegiantladder.com/ or contact 1-800-453-1192
To obtain information, visit http://www.bauerladder.com/safety-ladder/ or contact 1-800-321-4760
To obtain information, visit http://michiganladder.com/ or contact 1-800-444-6704
To obtain information, visit http://www.stokesladders.com/ or contact 1-800-842-7775
Lynn Ladder & Scaffolding Co., Inc.
To obtain information, visit http://www.lynnladder.com/ or contact 1-800-225-2510
To obtain information, visit http://www.wernerco.com/us or contact 1-888-523-3371
Tri Arc Manufacturing
To obtain information, visit http://tri-arc.com/ or contact 1-412-826-8531
To obtain information, visit http://www.coscoproducts.com/eng/Products/Specialty-Ladders/ or contact 1-800-554-1108
To obtain information, visit http://www.strongwell.com/ or contact 1-276-645-8000