As we discussed earlier, PV systems consist of multiple mechanical and electrical components, and so safety practices and procedures are critical to reducing or eliminating installation errors, electrical hazards, or injury (or death) on job sites. We saw that NEC has guides for safety requirements for designing and installing PV systems such as voltage and current limits, OCPD and ground-fault devices, and disconnects.
Aside from the aforementioned regulations, this section describes safety practices and procedures that must be used to install PV systems. PV is an electrical system, and workers can get injured. Non-electrical hazards are usually caused by human error, due to carelessness or failure to adhere to safety requirements. Installers should be alerted to different non-electric hazards they may encounter on the installation site. Cuts, bumps, falls, and sprains can cause as much hazard and lost time as electrical shock and burn hazards.
The Occupancy Safety and Health Administration (OSHA) creates a set of regulations that requires employers to provide a safe place for employees while reducing hazards. OSHA 29 CFR part 1926 applied to general construction practices includes several practices applicable to PV systems. OSHA 10 [1] is a recommended basic training for all workers.
In order for PV installers to reduce/eliminate their number of injuries, an awareness of potential hazards and a program where safety rules are frequently reviewed are required. This can be accomplished based on safety training series' offered to workers. Construction sites contain a number of risks that we will discuss in this section. Installers should know that these risks are continuously changing based on new materials and technologies, so regular updates on these topics are recommended.
There was a time when training was not available for workers to comply with safety regulations. One of the best, effective ways to convey the importance of complying with regulations is by illustrating real examples of incidents. For that reason, OSHA has put together a series of training videos to make training appealing to workers. Some of these videos on the following pages are directly related to PV installations and some are general examples of construction work related hazards. We encourage our solar professionals to watch all videos to get an idea about the importance of OSHA training and safety regulations in general.
Common electrical accidents are classified as:
These injuries can occur when electric current flows through the human body. The injury can become critical depending on the amount of current, the path through the body, and the duration. It is difficult to estimate when current will flow or the severity of the injury that might occur because the resistivity of human skin varies from just under a few ohms to several hundred thousand ohms depending primarily on skin condition and moisture. DC current generated by PV systems can cause continuous arc, and if it travels through a part of the body, it may cause serious burns. Power conditioning units are hazards, as they generate high AC voltage that can cause injuries as well.
This OSHA prevention video (5:41) describes how to prevent deaths and injuries from employees' contact with overhead power lines while using ladders. Find more information on this topic on the OSHA website [2].
This OSHA prevention video (3:53) describes how to prevent deaths and injuries from contact with overhead power lines while using cranes. Find more information on this topic on the OSHA website [2].
According to the OSHA website [6], Lockout/Tagout (LOTO) refers to "specific practices and procedures to safeguard employees from the unexpected energization or startup of machinery and equipment, or the release of hazardous energy during service or maintenance activities." This can be done by:
The following video (1:57) offers more information on this subject.
Any system with batteries forms a potential hazard. Some areas of concern include:
A fall is considered the primary cause of death in the construction industry. OSHA fall protection regulations apply to PV systems since PV systems can be installed in locations where climbing a ladder, working on roof, or use scaffolds is required.
A training on fall protection should be offered to workers on how to use fall protection systems and devices to avoid injuries that include:
The following video (26:25) discusses OSHA's fall protection policies for residential construction.
The following videos (3:21, 2:59, 3:06, 3:02, 3:03, and 3:10 respectively) cover various falls in construction.
There are two types of slopes that exist on roofs and special attention should be taken:
Require emergency stop switches at the operator station or the motor
At heights greater than 10 feet, the fall protection requirement for workers on scaffolds is different from the general construction requirement at 6 feet or greater. 29CFR1926.451(g)(1). See the following video (1:28) for more.
OSHA requires a signal person when:
Each power tool has its own set of requirements for use, and some come with safeguards. For most PV systems, workers will use electric power tools, air-filled tools, hydraulic tools, and tools that require liquids such as gasoline. Good understanding of the hazards associated with the power source will reduce the number of potential incidents and injuries.
Personal protective equipment (PPE) protects worker dangers, such as falling items, unsecured materials, and loud noises, that can cause injury. Examples of PPE include:
PV systems are installed where the sun is brightest and no shade exists. Sunburn and dehydration due to extreme temperature may occur.
Installers should pay attention to any of inhabitant in the site where the PV system will be installed. Serious injuries may occur due to neglect. The site may be treated against these hazards before the installation starts.
Most PV systems contain metal items with sharp edges and can cause injury if you are not careful. Installers should wear gloves when handling metal, particularly if you are drilling or sawing.
Many PV systems are installed in remote areas in rough terrain with different altitudes. Walking to and around the site, particularly carrying materials or test equipment, can result in falls and/or sprains. Installers should follow correct dress codes from head to toe.
The following videos (2:48 and 2:45, respectively) offer more on sprains and strains.
Metal left exposed in the sun can reach high temperatures that can cause serious thermal burns. In addition, most stand-alone PV systems contain acid batteries that can create acid burn hazards. Chemical burns will occur if the acid makes contact with an unprotected part of the body. Safety glasses and gloves are recommended for installers.
Links
[1] http://www.osha.com/courses/10-hour-construction.html
[2] http://www.osha.gov
[3] https://www.osha.gov/dts/vtools/construction/ladder_powerline_fnl_eng_web_transcript.html
[4] https://www.osha.gov/
[5] https://www.osha.gov/dts/vtools/construction/crane_powerline_fnl_eng_web_transcript.html
[6] https://www.osha.gov/dep/greenjobs/solar_loto.html
[7] https://www.osha.gov/video/shipyard_accidents/shipyard_accidents_video_transcript.html#v2_7
[8] https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10839
[9] https://www.osha.gov/dts/vtools/construction/falls_from_bridge_fnl_eng_web_transcript.html
[10] https://www.osha.gov/dts/vtools/construction/scaffolding_fnl_eng_web_transcript.html
[11] https://www.osha.gov/dts/vtools/construction/falls_floor_fnl_eng_web_transcript.html
[12] https://www.osha.gov/dts/vtools/construction/falls_leading_edge_fnl_eng_web_transcript.html
[13] https://www.osha.gov/dts/vtools/construction/reroofing_fnl_eng_web_transcript.html
[14] https://www.osha.gov/dts/vtools/construction/skylight_fnl_eng_web_transcript.html
[15] https://www.osha.gov/video/shipyard_accidents/shipyard_accidents_video_transcript.html#v1_6
[16] https://www.osha.gov/dts/vtools/construction/pullingcables_fnl_eng_web_transcript.html
[17] https://www.osha.gov/dts/vtools/construction/stone_laying_fnl_eng_web_transcript.html