Metal Stair Specs

Regulating Agencies

• Manufacturers must follow safety regulations set forth by OSHA, the Occupational Safety and Health Administration. In addition, the International Building Code and ANSI (National Standards Institute) set out specifications for stairs. Many regulations are the same for metal, wood or concrete stair construction, and many manufacturers offer staircase "code packages" that take all the guesswork out of staircase specifications when designing a building.

Railings

• According to OSHA, any stair that has at least four risers must have a handrail. Railing balusters cannot be more than 4 inches apart to prevent children from getting their heads stuck. Handrails should be between 1.5 and 2 inches in diameter. Handrails thicker than this, although they may be more pleasing architecturally, are hard to grasp, making it difficult to prevent a fall. You should be able to slide your hand down the railing without having to lift it over barriers. The railing must be at least 30 inches high – the minimum height to prevent people from accidentally falling over it.

Treads and Risers

• The stair tread surfaces must be slip-resistant, says OSHA. A staircase must be at least 22 inches wide, although most are wider. All risers must be the same height, with a maximum height of 9.5 inches. You may have noticed that stairs with higher risers are more tiring to climb. Stairs should angle at least 30 degrees but no more than 50. Again, a steeper grade is more difficult to climb.

Spiral Staircases

• A spiral staircase tread width must be at least 26 inches. This means that a total spiral staircase diameter of about 50 inches is adequate to meet code requirements. This makes spiral stairs a very efficient use of space when designing a home or business. Each tread must be a minimum of 7.5 inches deep measured at 12 inches from the inner end. Every tread must be identical in size.

Landings

• Any landings must be at least 30 inches in depth. OSHA does not specify the number of landings a staircase must have, but the National Safety Council suggests installing a landing after every 10th or 12th step.