CSA F300-13:2018 pdf download.Residential depressurization
4.2 Determining the level of depressurization
The level of depressurization shall be determined using either the predicted house depressurization calculation or the house depressurization field test if the conditions in Clauses 4.1.1 and 4.1.2 are present. The following shall apply for the predicted house depressurization calculation and house depressurization field test:
a) Predicted house depressurization calculation: If the predicted house depressurization calculation is performed, the protocol found in Form 1, "Predicted house depressurization", with or without a blower door test, shall be used to calculate the level of depressurization. If the house passes the predicted house depressurization calculation, no further action is required. If it fails the calculation,either a house depressurization field test shall be performed, or else mitigation solution(s) shall be implemented (see Clause 5).
Note: Even though the house may fail the predicted house depressurization calculation, it may pass the House Depressurization Field Test.
b) House depressurization field test: If a house depressurization field test is performed, the protocol in Form 2 shall be used to determine the level of depressurization. If the house passes the house depressurization field test, no further action is required. If the house fails the house depressurization field test, then mitigation solution(s) shall be implemented (see Clause 5).
Note: Both Form 1, "Predicted house depressurization" calculation and Form 2, "House depressurization field test" that follows are based on the concept of depressurization limits for appliances. This means that beyond a certain level of house depressurization (usually 5 Pa for chimney-vented appliances), there is a good possibility that proper venting of the combustion products will not occur, and that combustion spillage may occur. The goal of both test procedures is to verify that house pressures do not exceed this depressurization limit. It is strongly recommended that a house depressurization field test be conducted in addition to a manual calculation.
B.1.3 Volume of any enclosed space surrounding a fuel burning appliance(s)
An enclosed space around the appliance may better contain the by-products of combustion and limit dispersion of the by-products to the volume of air in the remainder of the building envelope. Depending on how air-tight this enclosure is, any depressurization could become localized to the enclosure.However, unless there is a dedicated source of outdoor air, an enclosed space potentially limits the appliance's access to fresh combustion and dilution air, which can further induce poor burning and increase carbon monoxide production.CSA F300-13 pdf download.