Sling tension from the load angle factor
Used on the ASP, CSP and CHST. The worked example below is computed by code and checked against the source.
LAF = 1 ÷ sin(horizontal angle) = sling length ÷ vertical height
Tension per leg = (load ÷ legs carrying it) × LAF
Angle measured from the horizontal. For bridles of 3 or more legs, DOE-STD-1090 has 2 legs carry the load unless even sharing is verified.
Worked example
DOE example: 1,000 lb on a 2-leg bridle at 45° from horizontal.
(1,000 ÷ 2) × 1.414 = 707 lb per leg
The source prints this result, and our code reproduces it.
OSHA's sling guidance says slings with horizontal angles under 30° should not be used.
Run your own numbers: sling angle calculator.
Where it appears on the exam
ASP: ASP11 Domain 1, Mathematical Calculations
Blueprint: ASP11 Domain 1, task 2: rigging and load calculations
Practice: Rigging and Sling Calculations
CSP: CSP11 Domain 1, Advanced Application of Safety Principles
Blueprint: CSP11 Domain 1, task 6: materials handling (rigging)
Practice: Rigging and Fall Clearance Calculations
CHST: CHST5 Domain 1, Hazard and Risk Identification and Control
Blueprint: CHST5 Domain 1, knowledge 9: hoisting and rigging
Practice: Rigging and Sling Calculations
Source
The formula comes from
DOE-STD-1090-2004, Hoisting and Rigging, 11.3.1.1 Load Angle Factor(opens energy.gov in a new tab)“1. Load = 1,000 lb. 2. Sling = 2-legged bridle. 3. Angle with horizontal = 45 degrees. 4. Load angle factor from Figure 11-7 = 1.414. b. Each of the two legs would lift 500 lb if a vertical lift were made. However, there is a 45 sling angle involved. Therefore, the 500-lb load would be multiplied by the load-angle factor in the chart, giving a total of 707 lb (500 lb x 1.414) tension in each sling leg. Each sling leg, therefore, must have a rated capacity of at least 707 lb.”
Questions
- What is the formula for sling tension from the load angle factor?
- LAF = 1 ÷ sin(horizontal angle) = sling length ÷ vertical height; Tension per leg = (load ÷ legs carrying it) × LAF. Angle measured from the horizontal. For bridles of 3 or more legs, DOE-STD-1090 has 2 legs carry the load unless even sharing is verified.
- Will this formula be given on the BCSP exam?
- BCSP says the formula is included in the question whenever one is needed, unless the question is testing whether you know the formula. You can't bring a formula sheet into the exam, so learn what each formula does and when to use it.
BCSP on formulas at the exam
BCSP, What to Expect When Sitting for a BCSP Exam (item 7)(opens bcsp.org in a new tab)“For any question requiring a mathematical formula, the formula will be included within the exam question (unless the question is specifically testing your knowledge of a formula). You will not be provided or permitted to bring a formula sheet.”
Related
- Excavation sloping (simple slope, 20 ft or less)
- Choker hitch capacity by angle of choke
- Personal fall arrest distances
- Secondary containment capacity
- ASP formula sheet
- CSP formula sheet
- CHST formula sheet
Checked 2026-10-16. Spot a problem? Email hello@passcited.com.