Helicopter guidelines for land seismic & helirig operations - OGP

Helicopter guidelines for land seismic & helirig operations
B.2.2
B.2.3
Design breaking strength and design factor: wire rope, straps, slings, shackles, and
swivels should have a design breaking strength of five (5) times the rated WLL (a
design factor of “5”). Synthetic fiber rope and slings require a higher safety factor and
breaking strength as synthetic materials are more vulnerable to the environmental
conditions. It is recommended to use a designed breaking strength of at least seven (7)
times the rated WLL (a design factor of “7”) for synthetic fiber rope and slings.
Proof testing: After manufacture, all items should be proof tested to twice the WLL
by the manufacturer or test facility. Test certificates are to be retained until the item is
scrapped and should provide the WLL, design factor or design breaking strength, and
the proof testing results.
Table 1: Example of OGP recommended working loads, and design and initial testing ratings
A helicopter will be lifting seismic drills weighing 1,850 pounds. Operator will use a cargo hook rated at
4,000 pounds maximum capacity. Shown are OGP guidelines for any item of lifting equipment.
OGP recommended
minimum WLL
of any lifting
equipment item
OGP recommended
design factor
(safety factor)
Minimum design
breaking strength
(by manufacturer)
Proof testing load
(by manufacturer or
test facility)
Calculation used Hook capacity Per ASME WLL x design factor 2 x WLL
Wire rope/sling 4,000 lbs. 5 20,000 lbs. 8,000 lbs.
Synthetic fiber rope 4,000 lbs. 7 28,000 lbs. 8,000 lbs.
B.3 Markings and records
Note: The manufacturer shall identify slings initially. The user shall maintain the sling
identification during the life of the sling. Replacement of the identification shall be considered a
repair to be completed by the manufacturer or person/organization approved in accordance with
recognized standards.
B.3.1
B.3.2
B.3.3
B.3.4
All cables, slings and straps should be tagged or marked to show the name or
trademark of manufacturer and the swaging collar embossed with:
1. A reference number.
2. Rated load limit (WLL). Note: Some countries may use SWL or “rated capacity.”
3. Diameter or size, and length of the sling.
4. Date of next formal inspection.
All other lifting items should be stamped or marked to show a reference number,
and WLL.
If it is not practical to mark the required items, a suitable color code should be used.
An appropriate maintenance program should be developed for all items, which
provides a traceable record of testing and inspections. A useful tool for this is a ‘sling
register’ in which a full inventory is kept of all slings and other lifting equipment
as well as the type of attachments and shackles etc., in use, documenting age, date
put into service, inspection and replacement cycle and dates and, where appropriate,
maximum wear allowed.
© OGP
47