6.2 General Installation Rules: Instructions, Access, Clearances & Garages (Clause 4)

Clause 4 of CSA B149.1 holds the general rules that apply to every installation before you reach the piping (Clause 6) or venting (Clause 8) chapters. In Ontario you read Clause 4 together with the Gaseous Fuels CAD, which rewrites several of its clauses.

1. Instructions, Approval and Installer Responsibilities

• Clause 4.1.3: an appliance, accessory, component or equipment is installed in accordance with the manufacturer's certified instructions and the code (except field-approved equipment, which Clause 4.1.4 sends to CSA B149.3).
• Ontario CAD clause 4.1.5: where the certified instructions and the code conflict, the more stringent of the two prevails.
• Clause 4.2 (approval): equipment must be certified or approved; Ontario's CAD (clause 4.2.3) sends field approval of an appliance's assembly or construction to Section 2.0 of the CAD, which adopts CSA B149.3-25.
• Clause 4.3 (installer responsibilities) covers compliance with the code, giving the user the instructions, following the manufacturer's instructions, using proper replacement parts, conversions, and gas-tightness and pressure testing (4.3.7).
• Clause 4.4 (training) requires qualified, trained personnel—in Ontario that means the right certificate under O. Reg. 215/01. Remember the G.3 limits: the four general-supervision tasks of s. 22(1), direct supervision for anything else, and never the initial activation of a new or newly converted appliance.

Conversions and damaged appliances

• Clause 4.5.4: when an appliance is converted to another gas, the gas it now uses is marked on the rating plate (for hydrogen-natural gas blends, the maximum hydrogen percentage too).
• Ontario CAD clause 4.3.5: when a new gas appliance replaces another form of energy, the installer must decommission the old supply—for an inside fuel oil tank, remove the fill pipe and cap the opening (leaving the vent pipe), shut and plug the tank outlet valve, and advise the owner in writing that the tank may have to be removed under the fuel oil regulation; for propane, shut the cylinder or tank valve and disconnect and cap the propane piping outdoors; for an electrical appliance, shut off the power and remove the fuse or turn off the breaker.
• Ontario CAD clause 4.5.5: an appliance that has been exposed to fire, explosion, flood or other damage may not be offered for sale, installed, re-activated or reconnected unless the authority having jurisdiction approves it or a G.1 or G.2 (as appropriate to its input) inspects it and confirms it is fit for continued use.

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2. Accessibility (Clause 4.14)

Clause 4.14 makes appliances accessible for inspection and service: general access for servicing (4.14.1–4.14.2), the access opening (4.14.3), the passageway (4.14.4), fixed access to rooftop installations (4.14.5), roof installations (4.14.6) and service platforms (4.14.7). Ontario amends three of these:

Clause 4.14.6(b) also sets a minimum clearance between a rooftop appliance and the roof edge; check the value and the guardrail alternative in your code book.

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3. Clearances to Combustible Material (Clause 4.13 and Table 4.1)

• The certified clearances on the rating plate and in the instructions are the starting point; you may never install closer than the manufacturer allows.
• Clause 4.13.2 and Table 4.1 allow a required clearance to be reduced only when one of the specified forms of protection is installed—for example sheet metal or insulating millboard spaced out from the combustible surface on noncombustible spacers. Table 4.1 gives the reduced clearance for each form of protection; read the value from the table rather than estimating a percentage.
• The spaced-out shield works because the ventilated air space, open at the top and bottom, lets convection carry heat away. Fastening sheet metal flat against drywall gives almost no protection.
• Paper-faced gypsum board is combustible for clearance purposes; only materials that meet the noncombustibility test (CAN/ULC-S114) are noncombustible.
• Clause 4.13.3 covers appliances of 400,000 Btu/h or less installed on combustible or masonry floors—use only appliances certified for the floor they sit on, or provide the protection the code requires.

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4. Garages (Clause 4.16)

Gasoline and solvent vapours have a vapour density of roughly 3 to 4 relative to air, so they collect at floor level. Clause 4.16 (storage garages 4.16.2, repair garages 4.16.3) keeps appliance burners and ignition devices raised above that vapour layer—the familiar rule is 18 in. (450 mm) above the floor; confirm the exact wording and exceptions in your code. Appliances certified for floor installation in a garage, such as flammable-vapour-ignition-resistant (FVIR) water heaters, are installed as their certification and instructions allow.

Ontario CAD clause 4.16.4: where a forced-air appliance that heats an attached residence is installed in a residential garage, the part of its return-air system inside the garage may have no openings, and the return air system must be airtight so garage air cannot be drawn into the house.

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5. Hazardous Locations, Ignition and Protection

• Clause 4.9 — hazardous locations, including areas with flammable vapours or combustible dust.
• Clause 4.10 — no smoking or other ignition source while working on gas-carrying parts.
• Clause 4.11 — safety devices must not be isolated or bypassed.
• Clause 4.12 — leak detection: never use a match or other ignition source (4.12.1); Clauses 4.12.2 and 4.12.3 deal with the light used and with electric switches near a gas leak—never operate a switch where gas may be present.
• Clause 4.23 — protect appliances from physical damage; Clause 6.16 adds posts or guardrails where vehicles could strike gas piping.
• Clause 4.24 — odourization (natural gas to CSA Z662, or approved gas detection).

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6. Rooms Where Appliances Are Restricted

B149.1 does not ban all appliances from bedrooms and bathrooms in one clause; the limits are appliance-specific and sit in Clause 7. Water heaters in bathrooms and bedrooms (Clause 7.27.1), room heaters in bathrooms (7.24.1), decorative appliances (7.25.4), hotplates and ranges in bedrooms (7.29.2, 7.33.1) and direct-vent appliance location (7.11) each have their own conditions. On the exam, go straight to the appliance's clause in Clause 7 rather than relying on a general rule.