OHS Code Explanation Guide

Published Date: July 01, 2009
Bookmark this page

Part 37 Oil and Gas Wells

Section 764 Ground anchors

Subsection 764(1)

Ground anchors must be pull-tested annually to ensure that they offer solid, stable securement for guy wires. The ground anchors must be tested according to

(a) API Recommended Practice RP 4G, Recommended Practice for Maintenance and Use of Drilling and Well Servicing Structures (2004),
(b) the manufacturer’s specifications, or
(c) specifications certified by a professional engineer.

Subsection 764(2)

There are four basic types of manufactured anchors:

(1) the screw or helix anchor;
(2) the expanding plate anchor;
(3) the flat plate anchor; and
(4) the pivoting anchor.

Installing anchors according to the manufacturer’s specifications satisfies the requirements for individual pull testing. Screw or helix type anchors have a direct correlation between anchor capacity and the torque required to install the anchor. Torquing according to the manufacturer’s specifications is an acceptable non-pull test method of determining anchor capacity.

Fabricated anchors should be designed by a professional engineer. Written procedures for installation must be prepared and certified. These anchors should be proof tested for structural integrity and holding capacity. Individual pull testing is not required if anchors are installed in according to the written procedures. Proof of installation protocols and proof-tested holding capacities are required.

In the absence of manufacturer’s specifications, the location diagram shown in Figure 37.4 may be used.

Figure 37.4 Example of anchor locations

Each zone requires an anchor of different holding capacity. If anchors are located in more than one zone, then all anchors should be of the capacity required for the greater capacity zone. See Table 37.2.

Table 37.2 Anchor capacity requirements for each zone

Anchor Capacity (tonnes)

Zone

Doubles Mast

Singles Mast

Post Mast

A

14.2

6.4

6.4

B

10.5

4.6

4.6

C

8.2

4.6

4.6

D

6.7

4.6

4.6

Anchor capacities shown assume the following:

  • adequate foundation support for mast and carrier
  • adequate crown-to-carrier internal load guys
  • maximum wind load – 120 kilometres per hour