Solution Summary: Designing Roofs with Permanent Roof Anchors
Designing roofs that include permanent roof anchor systems is a prevention through design (PtD) process that addresses worker exposure to potential fall hazards during construction, repair and maintenance of buildings. Installing permanent and structurally sound roof anchor systems provide strong and reliable tie off points for personal fall arrest systems.
The three components to a personal fall arrest system are: anchor, body harness and connector. This design solution specifically focuses on the inclusion of permanent anchors in the design of the roof and identification of the anchors on the design drawings such that they can be used as tie-off points for connecting personal fall equipment during the construction and maintenance activities over the lifecycle of a building.
According to OSHA, under 29 CFR 1926.502(d)(15), anchorages used for the attachment of personal fall arrest equipment shall be independent of any anchorage being used to support or suspend platforms and capable of sustaining a load of at least 5,000 pounds per employee attached without fracture or failure in the most adverse loading direction.
There are many different methods of securing an anchor to a structure in order to meet the load requirements. It is recommended to follow the manufacturer's specific instructions and safety guidelines when installing roof anchors.
Commerical roof anchors (Photo from Super Anchor Safety)
Residential roof anchor (Photo from Super Anchor Safety)
Working near unprotected roof edges, roof and floor openings, leading edges, and open shafts can expose workers to potential fall hazards when personal fall protection is not used. Falls from height typically result in severe injuries or death. In addition, structurally unsound anchorage points can contribute to the increased risk of falls.
How Risks are Reduced:
Risks are reduced and controlled by the personal fall arrest system, which is designed to prevent the employee from hitting the ground. Permanent anchors provide easily-accessible, secure places to tie off when personal fall protection is required. In addition, these anchorage points reduce the chance workers unknowingly connect their fall protection gear to something that may not be structurally sound or certified by a registered Professional Engineer.
Risks are reduced and controlled by the personal fall arrest system which is designed to prevent the employee from hitting the ground. Roof anchors are part of the system.
- Once installed it is generally the responsibility of the building owner to keep track of the inspection and maintainance of roof anchors to ensure their continued and reliable performance.
- Roof anchors should be annually inspected by a qualified person. The report of this inspection should be included in the building’s logbook and distributed to contractors prior to starting work.
- Roof anchors should be re-certified when there is re-roofing or renovating, or at periods not to exceed 10 years. The report of this inspection shall also be included in the building’s logbook.
- If the structural integrity of a roof anchor becomes suspect at any time, a test procedure shall be performed under the approval of a registered Professional Engineer.
- Post installation testing should include applying a minimum static load equal to half the maximum capacity of the anchor in the most adverse loading direction that the load might be applied. In this case, an anchor designed for a 5000 pound ultimate load should be tested at 2500 pounds.
- A well thought out plan for roof anchors can be beneficial during maintenance because workers will have a structurally sound, certified, convenient place to tie off.
- If an employee has fallen and the personal fall arrest system has been activated, the employee has two options. The first option is self rescue. The second option is the employee being rescued. Rescue can be accomplished through a variety of methods including mobile cranes, ladders, scissor lifts, and articulating booms.
Dangerous pendulum swings may result when a worker moves horizontally away from an anchor point and falls. The arc of the swing may produce significant speed that can propel the worker into an obstruction, causing injury or death. Swing hazards can be reduced by ensuring that anchor points are overhead of the worker at all times. Fall protection designs should include multiple overhead anchor points that employees can access when moving to a new position. Horizontal lifelines also provide continuous overhead attachment points. The force of the swing can be reduced by raising the height of the anchor point, reducing the angle of the arc.
Equipment Mixing and Mismatching
Employers and employees must both realize that components of a system may not be interchangeable. No component of a fall arrest system should be substituted or changed unless fully evaluated and tested by a competent person or the equipment manufacturer. When purchasing a fall protection system, it is best to purchase a complete system from a reputable manufacturer or authorized dealer.
Fall Rescue Plan
After a fall, a worker may not be able to rescue themselves and may remain suspended in a harness. A worker is at great risk of developing a condition known as "suspension trauma" if left suspended by a harness for a prolonged period. Suspension truama is a serious condition and can even be fatal. Onset of symptoms of suspension trauma can occur as little as 5 minutes after a fall. A rescue plan should be in place to retrieve a suspended worker as soon as possible after a fall. Make sure ladder trucks will be able to reach hanging workers. Or plan ahead for other ways to resue them. Be sure medical and rescue teams will get there fast if needed. Products are available to limit the risk of suspension trauma after a fall.
Le, Jean Christophe, MPH - CPWR - The Center for Construction for Research and Training
OSHA Alliance Program's Construction Roundtable
The designation of permanent roof anchors installed onto buildings will be dependent on the guidance from a competent person with structural engineering experience and federal regulatory standards. For more information regarding roof anchor applicability, please contact the roof anchor manufacturer directly. The information in this page was adapted from the Alliance Program Construction Roundtable
NIOSH Workplace Solutions Sheet
The National Institute of Safety and Health (NIOSH) has published a series of “Workplace Solutions”, which are easy-to-understand recommendations from NIOSH research results. Related to this Construction Solution, please find more information on: Preventing Falls from Heights through the Design of Embedded Safety Features and Supporting Prevention through Design (PtD) Using Business Value Concepts