Roof Tie Down Requirements

Building codes such as the icc s 2012 international building code section 2308 10 roof and ceiling framing typically specify that where rafter ties are used they are required at intervals ranging from 12 to 24 o c.

Roof tie down requirements.

Hvac hold down brackets are used to secure an hvac rooftop to a roof curb. As 1684 2 clause 9 6 1 states that continuity of tie down shall be provided from the roof sheeting to the foundations. Roof anchors can be as simple as a d ring connection or as complex as a complete lifeline system. Repairing storm damaged roofs tie down designs for tile and sheet roofs conforms to wind classifications of up to category n3 previously w41n designed to withstand a maximum gust wind speeds of 50 metres per second.

Rafter or truss uplift connection forces from wind asd pounds per connection a b c d e f g h. Fmcsa requires that cargo securement systems be capable of withstanding the forces associated with following three deceleration accelerations applied separately. Roof truss tie down this guide provides information relating to the fact that as 4440 does not specify tie down requirements and therefore reference should be made to as 1684 parts 2 and 3. Batten fixings should comply with the tie down requirements specified in as 1684 2 fixings for 45mm deep timber battens should be 1 x 75mm long no.

This section contains the following resource. Wind certification requires a professional engineer s pe stamp of approval to verify a hvac rooftop unit can safely withstand high wind gusts sustained winds or storms without separating from the roof curb or the roof curb separating from the roof. 1 inch 25 4 mm 1 foot 304 8 mm 1 mile per hour 0 447 m s 1 pound 0 454 kg 1 pound per square foot 47 9 n m 2 1 plf 14 6 n m. Anchor points are usually installed on the roof and are used to connect lanyards lifelines and other forms of tie off which prevent a worker from falling.

Longer screws may be required in n3 and n4 sites for some batten and rafter spacings. For pitched coupled roofs where there is net uplift that cannot be resisted by nominal nailing alone the code requires specific tie down fixings be installed. The uplift connection forces are based on a maximum 33 foot mean roof height and wind exposure category b or c. 0 5 g acceleration in the rearward direction.

This section contains the following resource. 14 type 17 screws for n1 and n2 site wind classifications. 0 8 g deceleration in the forward direction. Depending on the roof design and the roof rafter spacing.

0 5 g acceleration in a lateral direction.