Roof Tie Down Requirements

Fmcsa requires that cargo securement systems be capable of withstanding the forces associated with following three deceleration accelerations applied separately.

Roof tie down requirements. 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. 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. 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. Hvac hold down brackets are used to secure an hvac rooftop to a roof curb.

This section contains the following resource. These include the minimal nominal fixings for roof trusses where there is no net uplift. Tie down details for repair of storm damaged roofs in south east queensland page 2 of 13. 0 8 g deceleration in the forward direction.

0 5 g acceleration in the rearward direction. 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. 0 5 g acceleration in a lateral direction. Both permanent and temporary roof anchor points are available.

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. Rafter or truss uplift connection forces from wind asd pounds per connection a b c d e f g h. Roof anchors can be as simple as a d ring connection or as complex as a complete lifeline system. As 1684 2 clause 9 6 1 states that continuity of tie down shall be provided from the roof sheeting to the foundations.

Depending on the roof design and the roof rafter spacing. 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. The uplift connection forces are based on a maximum 33 foot mean roof height and wind exposure category b or c. 14 type 17 screws for n1 and n2 site wind classifications.

Longer screws may be required in n3 and n4 sites for some batten and rafter spacings.