Choker hitch capacity by angle of choke
Used on the ASP, CSP and CHST. The worked example below is computed by code and checked against the source.
Capacity = choker rating × angle factor
Over 120° 100%, 90–120° 87%, 60–89° 74%, 30–59° 62%, 0–29° 49%
Grade 80 alloy chain choker ratings (OSHA Table 3) apply at angles of choke over 120°.
Worked example
1/2 in Grade 80 chain, single-leg choker (9,600 lb), angle of choke 75°.
9,600 lb × 0.74 = 7,104 lb
Run your own numbers: sling angle and tension 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
OSHA, Guidance on Safe Sling Use: Tables and Figures, Table 3 and Fig. 2 (Angle of Choke)(opens osha.gov in a new tab)“TABLE 3 RATED LOAD FOR GRADE 80 ALLOY STEEL CHAIN SLINGS CHOKER HITCHES ... (2) Rated loads are for angles of choke greater than 120 degrees. ... Angle of choke, deg | Rated Capacity, % ... Over 120 | 100; 90-120 | 87; 60-89 | 74; 30-59 | 62; 0-29 | 49. NOTE: (1) Percent of sling rated capacity in a chocker hitch.”
Questions
- What is the formula for choker hitch capacity by angle of choke?
- Capacity = choker rating × angle factor; Over 120° 100%, 90–120° 87%, 60–89° 74%, 30–59° 62%, 0–29° 49%. Grade 80 alloy chain choker ratings (OSHA Table 3) apply at angles of choke over 120°.
- 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)
- Sling tension from the load angle factor
- 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.