What is SB-7 and does it matter for my Ottawa guard?

SB-7 is the Ministry's Supplementary Standard SB-7 for guards, and it still matters under the 2024 Ontario Building Code (O. Reg. 163/24): clause 9.8.8.2.(6) says guards built to MMAH Supplementary Standard SB-7 are deemed to comply with the guard loading rules. Table 9.8.8.2. sets those loads for guards within a dwelling unit: 0.5 kN/m or a concentrated load of 1.0 kN at the top, 0.5 kN over an area up to 300 mm by 300 mm on the infill, and 1.5 kN/m vertical. So SB-7 is one way a guard design shows it meets the loads; ask your carpenter or designer whether your guard follows SB-7 or is designed another way.

Here are the other guard rules inside a dwelling unit.

A guard is required where the drop is more than 600 mm. Inside a dwelling unit, the guard must be at least 900 mm (about 35 1/2 in.) high. Openings in the guard must stop a 100 mm (about 4 in.) sphere from passing through. The triangular space formed under a stair guard must stop a 150 mm sphere. Nothing between 140 mm and 900 mm above the floor may make the guard climbable, unless it can be shown not to be a hazard.

A few things carpenters and homeowners sometimes confuse: the 900 mm minimum is the guard height inside a house, not 1 070 mm. The 865 mm to 1 070 mm range is for handrails, which are a separate requirement measured from the nosing line of the stair. Do not mix the two numbers.

If your guard is at a loft, an open landing or an upper hall, the same 900 mm minimum and the sphere rules apply. If it is beside a stair, the climbability restriction also applies to the balusters or infill panels between 140 mm and 900 mm above the floor.

The next practical step is to measure the height of your existing guard from the floor and compare it with the 900 mm minimum, then ask a carpenter to check the sphere clearances in person before deciding whether the guard needs to be rebuilt or modified.