Ladder safety is an issue at work and at home. Requirements in the workplace can serve as a useful guide for ladder use at home. The following tips are adapted from OSHA's ladder standard. A few of the standard's provisions:
Both foldout (self-supporting) and leaning ladders should be able to support four times the maximum intended load. The exception to this is extra-heavy-duty metal or plastic ladders, which must be able to support 3.3 times the maximum intended load.
Ladders that lean against a wall or other support should be positioned at an angle that places the base of the ladder a quarter of the distance of its total height away from that support. So, for example, the base of a twelve foot leaning ladder should be positioned so its base is three feet away from the wall.
For non-commercial wooden ladders (that is, that have been made for the job) the angle should equal about 1/8 of the distance to minimize strain on ladder joints.
Position portable ladders so the side rails extend at least 3 feet above the landing.
Secure side rails at the top to a rigid support and use a grab device when 3-foot extension is not possible.
Foldout or stepladders should have a metal spreader or locking device to hold the front and back sections in an open position when in use.
Ladder rungs, cleats or steps should be parallel, level and uniformly spaced, between 10 and 14 inches apart. For extension trestle ladders, the spacing should be 8-18 inches apart on the base and 6-12 inches on the extension section. Rungs must be skid-resistant and shaped so that an employee's foot can't slip off.
Ladders must be kept free of oil, grease, wet paint and other slipping hazards, and must not be coated.
Additional tips from the National Safety Council:
Don't put a ladder in front of a door unless the door can be locked, blocked or guarded.
Make sure both side rails of the ladder have secure, level footing.
If you're using a ladder up high, secure it top to bottom so it won't slip.
Keep ladders away from electrical wiring or any operational piping, such as acid, chemical, or sprinkler systems.