Table Source: OBC

3.1.1.4.(3)For the purpose of substitutions described in Sentence (1),

(b) a maximum of two substitutions per dwelling unit may be made if substitutions are made in accordance with Table 3.1.1.4.C.

Notes to Table 3.1.1.4.C (IP)

1. Where nominal R values are given, then use of corresponding "U" or "effective R" values are permitted.
2. Where the required airtightness is achieved, simultaneous substitution of two components listed in this Table is permitted.
3. Use only Table 3.1.1.4.B or Table 3.1.1.4.C, not both.