How high does a guard rail have to be?
Guard rails must be at least 36″ high if the surface is 24″ above grade. They must be at least 42″ if the surface is 5’10″ (1.80m). Any railing that is less than 24″ above grade does not have to meet the guard rail standards in the building code. California changed their building code so that any guard rail 24″ or more above grade must be 42″ high. This is the only state that prohibits 36″ railings. You should obtain a copy of your applicable building code to ensure that these stipulations above are still valid as codes to change from time to time. How much lateral force along the top rail must a guard rail system withstand? A guard rail system must withstand a 200 lbf concentrated load at any point along the top rail. This value is 225 lbs in Canada as they use a metric value (1.0KN). Safety factors are also applied in different jurisdictions and can range from 1.5 to 2.5 for testing purposes. A 42″ high railing will experience greater leverage than a 36″ high railing. A guard rail sy
