OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 32 Excavating and Tunnelling

Section 447 Locating buried facilities

Subsection 447(1)

Major hazards can be encountered when digging into or otherwise disturbing an underground pipeline or other buried facility. In the case of natural gas or oil, a major explosion and fire are possible if the pipeline is penetrated or damaged. In the least case an environmental spill will result. Digging into a buried electrical cable could result in an electrical flash, a fire or worker electrocution.

Sometimes buried facilities are embedded in concrete. These may include conduit or utility lines placed under a parking area, roadway or concrete sidewalk. To prevent damage to the facility, the owner may have encased the line(s) in concrete. The locating requirements of this section also apply in such cases.

If a buried facility might be affected by activities that disturb the ground, then the employer must advise the owner of the buried facility of the proposed activities and request that the buried facility be identified and its location marked. The owner or the owner’s designate must be advised before the ground is disturbed.

Situations may arise in which the employer does not know the type of buried facility that may be present and therefore cannot contact the owner or the owner’s designate. Despite this, the employer must not begin disturbing the ground until buried facilities have been identified and their locations marked. In this case, the employer should request the locate.

Alberta One-Call Corporation (Alberta 1-Call) is a good starting point because its mandate is to prevent damage to buried electrical, gas and communication facilities. There is no charge to the owner or employer for using this service. Alberta One-Call can be reached toll free at 1‑800‑242‑3447.

However, other facilities such as underground storage tanks and sewer lines may also be present. Finding these may require the assistance of a different locator service. For a listing of companies offering locator services, readers should check their local telephone book under the heading “Utilities – Underground Location Service”, as well as the following contractor listing prepared by Alberta One-Call

For more information
Pipeline and Utility Locators in Alberta

Figure 32.4 shows the international colour code used for marking buried facilities.

Figure 32.4 International colour code used for marking buried facilities (http://www.albertaonecall.com/)

Subsection 447(2)

Once a survey has been completed and all appropriate buried or concrete-embedded facilities marked, the employer must ensure that workers have been informed accordingly.

Subsection 447(3)

Since the original locate marks can be disturbed or destroyed by activities at the site or with progressive excavation, the marks must be re-established as often as necessary to ensure the safety of workers.

Subsections 447(4) and 447(5)

If the planned activity does not involve excavation or removal of soil, and overall penetration of the ground is 1 metre or less – placement of survey stakes, pin flags, etc. – the employer may use as-built drawings of the buried facilities for locating purposes rather than contacting Alberta 1 Call for a locate. The use of as-built drawings to locate the buried facilities, in combination with the shallow depth of ground penetration, protects workers from potential injury. Although the employer is not required to notify the buried facility owner of the planned activity, doing so should be done as a matter of good practice.

As-built drawings change to reflect modifications to, or maintenance of, installed buried facilities. The as-built drawings used by the employer must therefore be certified by the owner as being the most current drawings of record available.