Chapter 1

Introduction

This document is a guide to the health and safety practices in the tunneling industry in general, and is based on BS 6164-2011 “Code of Practice for Occupational Health and Safety in Tunneling”. It includes health and safety recommendations for tunneling construction practiced in Alberta. The document also covers cut and cover tunneling, shaft sinking construction, and maintenance and repair. The scope is limited to tunneling construction in general and does not include special tunnelings, such as mineral extraction and shaft construction.  

The Risk Control

Tunneling industry is a special division of the construction industry; it requires skilled crews that are specialized in tunnel construction. Tunneling construction is a risk-prone industry; a small mistake can lead to complete failure or major damage to the project.

Hazard Identification for a Safe Work System

Effective hazard identification is necessary in order to prevent any risk arising from hazards. Good health and safe work performance must be the priority of the construction team. The entire team is responsible for creating a safe workplace, identifying hazards, and helping to develop a safe construction process and environment. Risk identification and controlling is a continuous learning process that requires a team effort. Consistently, the risk identified should be avoided by taking preventive measures and should be recorded in a database for preventing future occurrences. The process should be carried out on a regular basis from the construction to the maintenance phase of the tunneling works.

Hazards in the tunneling industry may arise from the unstable ground, noise, dust, water, moving machinery, contaminated soil, the presence of gases, and many more. The hazards have the potential to harm a person working or living in the proximity of the construction area. The risk is directly proportional to the likelihood of occurrence of harm and the consequences if it does occur. The tunneling industry is a low frequency, but the high consequences industry and the occurrence of any incident may be deleterious.

A structured approach should be undertaken to reduce risks and should include the following stages:

In general, the types of accidents in the tunneling industry are similar in nature to those in the construction industry. The accidents should be recorded promptly to help identify any future risks and to reduce their occurrences. The following are examples of the types of accidents in the tunneling industry, 

Falling From a Height

Falls from height are more common in construction. Examples include falling off a ladder, which may result in severe injuries, or falling down a shaft while working near a deep excavation. 

Safety Measures -  Preventive measures should be taken in order to minimize such risks. A fixed barrier near the face of the excavation can reduce the risk of falling from a height. 

Falling on Level

Statistics of tripping and falling hazard injuries and casualties on construction sites are disturbing. The output can be nonfatal injuries to death in extreme cases. Common causes are messy and unorganized worksite, tools wires often plugged in, and electric cords laid unorganized on the worksite. In addition to the previously mentioned causes, underground tunneling construction can be categorized under work where poor visibility often prevails. The ground conditions are often uneven and slippery due to damp or moist environments.

Safety Measures – Improving site layout to permit clear vision and safe access, and planning and installing proper lighting may reduce risk. Ensuring good housekeeping standards incorporated in the contract documents is helpful to enforce clean construction sites. Additionally, the walkway should be kept clear all the time. Also, proper safety shoes should be provided on the job site. In the event of slippery conditions, proper warning signs must be installed. 

MUST KNOW

Alberta Occupational Health and Safety Code Relevant to the Topic 

According to the Alberta Occupational Health and Safety Code (current as of January 1, 2019) an employer must follow the following:

According to Part 2, Section 7(1)

An employer must assess a work site and identify existing and potential hazards before work begins at the work site or prior to the construction of a new worksite.

According to Part 2, Section 7(2)

An employer must prepare a report of the results of a hazard assessment and the methods used to control or eliminate the hazards identified.

According to Part 2, Section 7(3)

An employer must ensure that the date on which the hazard assessment is prepared or revised is recorded on it.

Note: Part 2: 7(2) and 7(3) do not apply to an emergency response during the period that emergency action is required.

According to Part 2, Section 7(4)

An employer must ensure that the hazard assessment is repeated

(a) at reasonably practicable intervals to prevent the development of unsafe and unhealthy working conditions,

(b) when a new work process is introduced,

(c) when a work process or operation changes, or

(d) before the construction of significant additions or alterations to a work site.

According to Part 2, Section 8(1)

An employer must involve affected workers in the hazard assessment and in the control or elimination of the hazards identified.

According to Part 2, Section 9(1)

If an existing or potential hazard to workers is identified during a hazard assessment, an employer must take measures in accordance with this section to

(a) eliminate the hazards, or

(b) if elimination is not reasonably practicable, control the hazard.