9.10.4.1.Mezzanines Not Considered as Storeys

(1) Except as required by Sentences (2) and 9.10.4.2.(1), the space above a mezzanine is permitted to be excluded from the calculation of building height, provided (a) the aggregate area of mezzanines that are not superimposed does not exceed 10% of the floor area of the building in which they are located, and (b) the area of mezzanine in a suite does not exceed 10% of the area of that suite on the storey on which it is located. (2) Except as required by Sentence 9.10.4.2.(1), the space above a mezzanine is permitted to be excluded from the calculation of building height, provided (a) the aggregate area of mezzanines that are not superimposed does not exceed 40% of the open area of the room in which they are located, and (See Note A-3.2.1.1.(3)(a)) (b) except as permitted in Sentence (3), the space above the mezzanine floor is used as an open area without partitions or subdividing walls higher than 1 070 mm above the mezzanine floor. (3) The space above a mezzanine conforming to Sentence (2) is permitted to include an enclosed space whose area does not exceed 10% of the open area of the room in which the mezzanine is located, provided the enclosed space does not obstruct visual communication between the open space above the mezzanine and the room in which it is located. (4) For the purpose of determining occupant load, the areas of mezzanines that are not considered as storeys shall be added to the floor area of the storey on which they are located. (See Note A-9.10.4.1.(4)) (5) Platforms and catwalks intended solely for periodic inspection and maintenance need not be considered as floor assemblies or mezzanines for the purpose of calculating building height, provided (a) they are not used for storage, and (b) they are constructed with noncombustible materials, unless the building is permitted to be of combustible construction.