Roundsling Information

Common Types
of Sling Hitches

Hitch	Comments
Vertical Hitch	One end is placed on the hook, while the other end is attached directly to the load. A tagline should be used to prevent load rotation.
Choker Hitch	Sling passes through one end around the load and the other end is placed on the hook. Rated capacity is normally 80% of that for a vertical hitch. Load control is a potential problem with only one sling rigged in a choker hitch. Also, the choke point should always be on the sling body—not on the fittings, base of the fitting or tag.
Basket Hitch	The sling cradles the load while both ends are attached overhead. The rated capacity for a basket hitch is twice that for a vertical hitch. As with the choker hitch, more than one sling rigged in a basket hitch (or some other means) may be necessary to help ensure load control.

Increased sling tension as a function of sling-to-load angle

Angle “A” in degrees from horizontal	Tension Multiplier
90	1.000
85	1.004
80	1.015
75	1.035
70	1.064
65	1.104
60	1.155
55	1.221
50	1.305
45	1.414
40	1.555
35	1.742
30	2.000
	Multiply the load weight (per leg) by the tension factor to determine the increased tension of the sling leg(s)

Reductions in rated capacity as a function of angle of choke

Angle of Choke (degrees)		Angle of Choke Reduction Factor
= or >	<
120	180	1.000
105	120	0.82
90	105	0.71
60	90	0.58
0	60	0.50

The radii values apply to roundslings that are fully tensioned to their rated capacity regardless of the hitch.

When roundslings are tensioned to lower force values, the minimum radius values will reduce accordingly.

Fractional inches are rounded up to the nearest 1/16” (1.58 mm).

Actual Sling Capacity =
Rated Capacity x
Reduction Factor

Minimum edge radii suitable for contact unprotected polyester roundslings

Sling Size	Vertical Rated Capacity		Min. Edge Radii		Min. Edge Radii		Sling Width at Load
	lbs.	kgs.	inch	mm	inch	mm	inch	mm
1	2,600	1,200	0.14	3.55	3/16	4.76	0.97	24.63
2	5,300	2,400	0.21	5.33	1/4	6.35	1.29	32.76
3	8,400	3,800	0.26	6.6	5/16	7.93	1.66	42.16
4	10,600	4,800	0.3	7.62	5/16	7.93	1.78	45.21
5	13,200	6,000	0.33	8.38	3/8	9.52	2	50.8
6	16,800	7,600	0.4	10.16	7/16	11.11	2.13	54.1
7	21,200	9,600	0.41	10.41	7/16	11.11	2.62	66.54
8	25,000	11,400	0.44	11.17	7/16	11.11	2.85	72.39
9	31,000	14,100	0.5	12.7	1/2	12.7	3.15	80.01
10	40,000	18,200	0.56	14.22	9/16	14.28	3.57	90.67
11	53,000	24,100	0.67	17.01	11/16	17.46	4	101.6
12	66,000	30,000	0.72	18.28	3/4	19.05	4.6	116.84
13	90,000	40,900	0.87	22.09	7/8	22.22	5.22	132.58

Roundsling Removal from Service Criteria

If Roundsling identification tag is missing or not readable
Holes, tears, cuts, embedded materials, excessive abrasive wear, or snags that expose the core yarn of the Roundsling.
Broken or damaged core yarn.
If Roundsling has been tied into one or more knots.
Acid or caustic burns of the Roundsling.
Melting, charring or weld spatter of any part of the Roundsling.
Distortion, excessive pitting, corrosion or other damage to fitting(s).
Broken or worn stitching in the cover which exposes the core yarn.
Any conditions which cause doubt as to the strength of the Roundsling.

Suitable connection hardware sizes for Polyester Roundslings when used in Choker and Vertical hitches

	Roundsling					Minimum	Hardware	Size
Sling Size	Rated Cap. Vert. Hitch		Stock	Dia.	or	Thickness	Effective	Contact	Width
	lbs.	kgs.	inch	mm	inch	mm	inch	mm	inch	inch
1	2,600	1,200	0.39	9.9	7/16	11.11	0.97	24.63	1	25.4
2	5,300	2,400	0.59	14.98	5/8	15.87	1.29	32.76	1-3/8	34.92
3	8,400	3,800	0.72	18.28	3/4	19.05	1.66	42.16	1-3/4	44.45
4	10,600	4,800	0.85	21.59	7/8	22.22	1.78	45.21	1-7/8	47.62
5	13,200	6,000	0.95	24.13	1	25.4	2	50.8	2	50.8
6	16,800	7,600	1.12	28.44	1-1/8	28.57	2.13	54.1	2-1/8	53.97
7	21,200	9,600	1.15	29.21	1-3/16	30.16	2.62	66.54	2-5/8	66.67
8	25,000	11,400	1.25	31.75	1-1/4	31.75	2.85	72.39	2-7/8	73.02
9	31,000	14,100	1.41	35.81	1-1/2	38.1	3.15	80.01	3-1/4	82.55
10	40,000	18,200	1.6	40.64	1-5/8	41.27	3.57	90.67	3-5/8	92.07
11	53,000	24,100	1.9	48.26	2	50.8	4	101.6	4	101.6
12	66,000	30,000	2.05	52.07	2-1/8	53.97	4.6	116.84	4-5/8	117.47
13	90,000	40,900	2.46	62.48	2-1/2	63.5	5.22	132.58	5-1/4	133.35

Where to Find Additional Information

WSTDA-RS-1 – Recommended standard specification for synthetic polyester roundslings
WSTDA-RS-1HP – Recommended standard specification for high performance yarn roundslings
WSTDA-RS-2 – Recommended operating and inspection manual for synthetic polyester roundslings
ASME B30.9 – Synthetic roundslings: selection, use and maintenance. OSHA Guidance on safe sling use (Guidance on Safe Sling Use (osha.gov))
OSHA 29 CFR 1910.184 Slings
Rigging handbooks
Formal training from certified third party or manufacturer

Phone

Email

Roundsling Information

Common Types
of Sling Hitches

Increased sling tension as a function of sling-to-load angle

Reductions in rated capacity as a function of angle of choke

Actual Sling Capacity =
Rated Capacity x
Reduction Factor

Minimum edge radii suitable for contact unprotected polyester roundslings

Roundsling Removal from Service Criteria

Suitable connection hardware sizes for Polyester Roundslings when used in Choker and Vertical hitches

Where to Find Additional Information

504-279-5225

Phone

Email

Address

Phone

Email

Roundsling Information

Common Typesof Sling Hitches

Increased sling tension as a function of sling-to-load angle

Reductions in rated capacity as a function of angle of choke

Actual Sling Capacity =Rated Capacity xReduction Factor

Minimum edge radii suitable for contact unprotected polyester roundslings

Roundsling Removal from Service Criteria

Suitable connection hardware sizes for Polyester Roundslings when used in Choker and Vertical hitches

Where to Find Additional Information

504-279-5225

Phone

Email

Address

Common Types
of Sling Hitches

Actual Sling Capacity =
Rated Capacity x
Reduction Factor