STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

Derricks and Portable Masts 517
1. Inspect welds in erecting mechanism for cracks and other signs of
deformity.
2. Follow the manufacturer’s instructions in checking hydraulic circuits
before lowering operation. Make sure of adequate supply of hydraulic
fluid.
3. Wire rope, including operating lines, raising lines, and guy lines, should
be inspected for kinks, broken wires, or other damage. Make certain that
guy lines are not fouled and that other lines are in place in sheave grooves
before raising or lowering operation.
4. Check safety latches and guides in telescoping mast for free operation
before lowering operation. Keep latches and guides clean and properly
lubricated.
5. Check unit for level and check foundation and supports for correct
placement before erecting operation.
6. Check lubrication of crown sheaves.
7. Check lubrication and condition of bearings in all sheaves, sprockets, etc.
8. Check folding ladders for free operation before lowering operation.
9. During drilling operations, it is advisable to make scheduled inspections
of all bolted connections to ensure that they are tight.
10. The visual field inspection of derrick or mast and substructure procedure
is recommended for use by operating personnel (or a designated representative)
to the extent that its use satisfies conditions for which an
inspection is intended. A sample report form for this inspection procedure
can be found in API Standard 4F. Forms are also available from International
Association of Drilling Contractors (IADC).
Splicing locks should be checked frequently for locking position or tightness,
preferably on each tour during drilling operations. To develop its rated load
capacity, the axis of the structure must be in alignment throughout its length.
It is important that any splice mechanism or locks be maintained in such
condition as to ensure structure alignment.
Guying for Portable Masts with Guy Llnes
This recommendation is applicable for most conditions encountered in the
use of this type mast. There will be exceptions where location clearance, ground
conditions, or other unusual circumstances require special considerations. Figure
4-5 shows a recommended guying pattern that may be used under general
conditions in the absence of an authorized API manufacturer’s recommendations.
Guy lines should be maintained in good condition, free from rust,
corrosion, frays, and kinks. Old sand line is not recommended for guy lines.
All chains, boomers, clamps, and tensioning devices used in the guy lines shall
satisfy the mast manufacturer’s recommendations. In the absence of mast
manufacturer’s recommendations, the following minimum breaking strengths
should be maintained: load guy lines-1 8 tons; external guy lines-12 tons;
racking board guy lines-10 tons.
Guy Line Anchors for Portable Masts with Guy Lines
Guy line anchors including expanding anchors, concrete deadmen, or any
other approved techniques are acceptable. The soil condition may determine
the most applicable type. Recommendations for anchor design and testing
are as follows: