| epa.gov | Environmental Protection Agency |
| nema.org | National Electrical Manufacturers Association |
| nari.org | National Association of the Remodeling Industry |
| smacna.org | Sheet Metal and Air Conditioning Contractors' National Association (SMACNA) |
| osha.gov | Occupational Safety and Health Administration (OSHA) |
| nspe.org | National Society of Professional Engineers |
| nist.gov | National Institute of Standards and Technology (NIST) |
| nfpa.org | National Fire Protection Association |
| necanet.org | NECA - National Electrical Contractors Association |
| ncma.org | National Concrete Masonry Association |
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