770
Ceiling Performance Specifications: Performance Criteria
775.1.8
The ceiling, except for finishes, will be regarded as a more or less
permanent part of the building shell, along with the structure, exterior walls
and major service mains.
775.2
REQUIREMENTS
775.2.1
Vertical Loads
The ceiling shall provide a platform over its entire upper surface, capable
of supporting some of the distribution components located in the service
zone, HVC terminals, and workmen engaged in construction,
maintenance, repairs and alterations. It must also provide support for
ceiling-hung items such as cubicle tracks, TV consoles, etc. These shall
be calculated as a uniform live load of 40 psf. The ceiling shall withstand
upward point loads of at least 25 pounds over a six-inch square area
without appreciable deformation. Deflection of ceiling base material shall
be limited to 1/360 of the distance between supporting members under full
live load.
775.2.2
Lateral Loads
The ceiling is not required to contribute to the lateral force resistance of
the structure, but it shall transmit all lateral forces developed in partitions,
as well as within the ceiling itself, to the structure.
775.2.3
1. The ceiling shall provide a sound barrier between the service zone and
the functional zone of Sound Transmission Class (STC) 40.
2. Ceiling surface treatment shall have a minimum absorption capability
of Noise Reduction Coefficient (NRC) 60.
775.2.4
Fire Safety
The ceiling shall be non-combustible and shall have a fire resistance
rating of one hour. Maximum flame spread rating of surface materials is
25 and maximum smoke developed rating is 50. When burnt, surfaces
shall not produce noxious or toxic fumes.
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