One of my favorite tv shows as a kid was "Lost in Space". It was ahead of it's time in the early 70's. The best character on the show was "Robot". He was always there to warn eveyone and save the day. He certainly would have sounded many warnings if they had stairs and rails on the ship, but it had a huge ramp and an elevator. Oh, there was also an emergency ladder from the lower level, but that is another issue and danger all it's own.
Stairs and Handrails are one of the most important hazards around your house, yet they can also be the most overlooked and are most often taken for granted. Just about every building made by man has stairs and handrails. Some are done to code and correctly, while others are a trap just waiting for some unsuspecting person to travel up or down them and trip and tumble to certain injury and pain, if not worse.
Here is a photo of an exterior set of steps with some serious problems. It's hard to believe that someone did this installation with good conscience.
Notice the rails posts at the bottom step are clearly missing the mark and just sort of dangling there with no purpose.
This photo of the same stair shows the inconsistancies of the risers. This, along with poor lighting is a disaster waiting to happen to some poor soul. Just count the brick coarses and that will give you an idea of difference in riser heighth.
Here is a rail system on an elevated deck. Rail height and more importantly, balaster and picket spacing is critical for the safety of toddlers and young children. The large spacing in this rail system will allow a toddler to possibly fall to certain injury, or worse.
The National Safety Council reports 12,000 stair deaths per year, with half of these deaths occurring in the home. This makes accidents from stairs second only to automobile accidents as the major cause of unintended injuries in the United States.
Building code requirements for stair depth and width vary from place to place and generally apply to new construction. Making stairs in older homes meet these requirements may not be feasible. A home inspection can make you aware of these type of safety issues.
Top Hazards in Stair and Rail Installation
- Balusters: when improperly spaced, more than 4" of space, a child can slip through or can get their head caught.
- Circular or Helical Stair: tread at center post too narrow, stair not ergonomically designed for safety.
- Flight too long: too many steps causes fear of falling or fear of height.
- Angle: stair too steep.
- Handrail / Safety-Rail: not ergonomically designed, improper finger clearance, railing is missing, loose, broken, not strong enough, too large, too wide, too thin, not continuous from landing to landing, not smooth, too hot, too cold, splintery, not maintained, not sanitary looking and not of a contrasting color with background.
- Platform or Landing: surface not slip resistant and has a sharp object, blunt wall or window in the possible fall direction.
- Nosing: missing, broken, worn, patched, loose, slippery, abrupt raised upper surface, sharp corners, not installed properly.
- Riser: not equal height on all steps in the flight; missing; shifted out of stringer; open type with too much over-hang from the step above, too little over-hang.
- Stringers: broken, loose, twisted, extends above the top landing or platform, extends beyond the bottom step, top surface of the stringer extends into the stairwell three or more inches behind the handrail or the side without a handrail.
- Tread: broken, loose, narrow, worn, highly abrasive, missing, shifted out of stringer, material not constant in the flight, not a slip resistant surface, surface slip resistance not consistent in the flight, loose carpet, torn carpet, debris, improper repair.
- Tread slope: for exterior stairs: nonexistent for proper drainage, or too steep.
- Geometry: tread/riser relationship in flight not constant, does not conform ergonomically to known and accepted safety standards
- Lighting: below the accepted safety standards, too many shadows, a dark corridor and corners leading to a stair.
- Sharp or Pointed Corners: on stair elements or hardware.
- Construction: Abrupt wall or window at the bottom of a stair's landing or platform.
- Low Headroom: 6′ feet - 8″ inches is standard, 7′ foot - 6″ inches is optimum in today's standards.
- Abrasive: wall surfaces, stair elements or hardware.
The most critical characteristic of stairs, even more important than the size of any of the parts, is that every step be the same. In fact, building codes enforce this rule. Fire and building codes devote a lot of space to stairs.
Many different terms have been used in describing stairs; I will use those defined in the illustration below. The ratio of unit rise to unit run determines the angle of the stairs.
The 1996 Council of American Building Officials (CABO) and the 2000 International Code Council recommendations call for unit runs to be not less than 10 inches and unit rises not more than 7¾ inches.
Nosing projection and open risers
Staircases which consist only of treads are said to have "open risers." Under the 1996 CABO model code, open risers are no longer permitted because they are a danger to children. They are also a danger to the elderly, who tend to catch their toe on the tread and trip. Nosing projections are also a danger to the elderly.
Again, limits are probably specified in the local building code. Typically the minimum width permitted in residences is around 2 feet 8 inches. Three feet is better, and 3′6″ is the standard for normal occupancy. If a stair is more than 44 inches wide, a handrail is required on both sides.
Most fire codes do not allow stairs to rise more than 12 feet without providing a landing. The length of the landing should be at least equal to the width of the stair tread.
Balustrade (vertical members of the rail system)
According to the 1996 CABO code, the openings between balusters is to be no greater than 4 inches. This is half of what was allowed a few decades ago; smaller holes reduce injuries to young children. The balustrade is topped by a handrail 30 to 38 inches above the top of the stringer; the handrail's grip size is between 1¼ to 2 inches. If the handrail is mounted on a wall, a space of at least 1½ inches must be left between the edge of the handrail and the wall.
Among American architects, an old rule-of-thumb is that the sum of the unit rise and the unit run should be about 17½″. Common practice has been to make the unit rise about 7½ inches, the unit run 9″ for interiors and 11″ for exteriors.
In modern times, stair researchers have gone beyond observing which existing stairs cause the most accidents. Using tools like endless mechanically driven staircases with variable unit rise and unit run, they have been able to experiment with many combinations of unit rise and unit run, and to capture in stroboscopic photography how missteps occur. The results largely confirm the rules of thumb, but some interesting results where observed, such as that the optimal rise/run ratio for descent is not the same as the one for ascent. Several researchers feel that for descent the unit run should be at least 11 inches.
But requiring an 11″ unit run is controversial. Increasing the unit run even an inch or two can greatly increase the size of the staircase. With a rise of 12 feet and a unit rise of 7.2 inches, increasing the unit run from 9″ to 11″ makes the staircase two feet longer-probably 6 square feet of floor area carved out of the living room. When a "7-11" standard was adopted by a building code in the Northeast, the National Association of Home Builders got it reversed, arguing that it increased costs without any proof that it was safer.
Alternate Tread Stairs
Imagine climbing a staircase in which alternate halves of the treads have been removed. A foot moving to the next empty tread does not need to clear the tread on which the other foot stands. Such staircases exist. Their great advantage is that they can be very steep (up to 70°, compared to up to 50° for normal stairs) and still be safe and comfortable. The great disadvantage is that such a staircase can accommodate only one person at a time. Such staircases are most commonly found on shipboard. In the United States, Lapeyre Stair in New Orleans specialized in such staircases.
I hope that this information helps everyone understand more about stairs and rail systems. Please share this info with anyone that you think needs it. Safety should be #1 around your home, don't take it for granted!!
This information is provided by David Holden, DRH Home Inspection in the Akron Ohio, Summit County Ohio Area.