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STANDARD FOR THE CONTROL OF GAS HAZARDS

ON VESSELS TO BE REPAIRED OR ALTERED

Short Title

1. This standard may be cited as the Gas Hazard Control Standard.

PART I

APPLICATION AND INTERPRETATION

APPLICATION 

• Scope

• Purpose

• Emergency Exemption

• Governmental Regulations

INTERPRETATION

• Definitions

• Materials

• Repair Classifications

• Tanker Designation

• Vessel

AND STANDARD SAFETY DESIGNATIONS 

Application ^

Scope ^

2. (1) This standard applies to vessels, including ships, barges, rigs and similar floating structures.

(2) This standard applies to vessels carrying or burning as fuel flammable or combustible liquids; it also applies to vessels carrying or having carried flammable compressed gases, chemicals in bulk, or other products able to create a hazardous condition.

(3) This standard describes the condition required before a space may be entered, or work may be started, on any vessel repair or alteration.

(4) This standard applies to cold work, application or removal of protective coatings, and work involving riveting, welding, burning, or similiar fire-producing operations.

(5) This standard applies to vessels in Canadian waters and to all Canadian-registered vessels, both within and outside of yards for ship repair or alteration.

(6) This standard applies specifically to those vessel spaces subject to concentrations of combustible, flammable, and toxic liquids, vapors, gases, and chemicals (refer to section 6); the standard also applies to those spaces that may not permit safe entry due to insufficient oxygen or excess oxygen.

(7) As defined and allowed in the ² Safe Working Practices" Regulations, a "qualified person" may carry out the functions of a marine chemist.

Purpose ^

3. This standard provides minimum requirements and conditions for use in determining that a space or area on a vessel is safe for entry or work (see illustrations in Appendix A).

Emergency Exemption ^

4. Nothing in this standard shall prohibit the immediate drydocking of a vessel in peril (e.g., in a sinking condition or by having been seriously damaged), thereby making it impracticable to clean and free of gas in advance; nonetheless all necessary precautionary measures should be undertaken as soon as practicable to provide safe conditions satisfactory to the marine chemist.

Governmental Regulations ^

5. Nothing in this standard shall supersede existing more stringent requirements of any governmental or local authority.

Interpretation ^

Definitions ^

6. In this Standard, unless the context otherwise requires,

² coiled vessels² means tank vessels using a closed system of heating coils carrying thermal oil as the heating media;

² hollow structures² means rudders, rudder stocks, skegs, castings, masts and booms, rails and other vessel attachments that enclose a void space;

11 ² marine chemist² means a person who has

1. graduated from a recognized educational institute and has completed
   
   (i) courses in chemical engineering, or

   (ii) a general course with a major in chemistry; or

2. obtained a fellowship in the Chemical Institute of Canada;
   
   
3. at least three years' experience in chemical or engineering work after completing the educational requirements, of which a minimum of 150 working hours shall have been spent under the supervisor of a marine chemist on shipboard work involving the testing and inspection of tank vessels and other vessels in the application of the Gas Hazard Control Standard TP 3177; and
   
   
4. shall have evidenced where certifying "flamable cryogenic liquid carriers," the required additional experience, training and knowledge necessary for these vessels.

The activities of a marine chemist are limited to the inspection and certification, procedures described in this standard and associated consulting services.

² marine chemist's certificate² means a written statement issued by a marine chemist in the form and manner prescribed by this standard; it states the conditions that the marine chemist found at the time of inspection.

Materials ^

1. ² chemical² means any compound, mixture, or solution, as a solid, liquid, or gas, that may be hazardous because of its properties other than or in addition to flammability, or because of the properties of compounds that might be produced by hot or cold work.
   
   
2. "combustible liquid" means any combustible liquid with a flashpoint above 27 degrees Celsius;
   
   
3. "flammable" and "inflammable" are synonymous; 
   
   
4. "flammable compressed gas" means any flammable gas compressed and/or liquefied for transportation, and with a Reid vapor pressure exceeding 276 kPa;
   
   
5. "flammable liquid" means any liquid with a flashpoint (closed cup) below 27 degrees Celsius and a vapor pressure not exceeding 2069 mm Hg at 27 degrees Celsius;
   
   
6. "lower flammable limit" and "lower explosive limit" are synonymous;
   
   
7. "toxic material" means any material that can produce injury, depending on concentration, rate, method of use, site of absorption, the person's general state of health, and differences between individuals.

Repair Classifications ^

1. "hot work" means any repair or alteration involving riveting, welding, burning, or similar fire-producing operations; grinding, drilling, sand-or shot-blasting, or similar spark-producing operations are considered hot work except when circumstances do not necessitate a classification;
   
   
2. "cold work" means any repair or alteration without heat, fire, or spark-producing operations;
   
   
3. "work below deck" means work in or on enclosed spaces surrounded by shells, bulkheads and overheads;
   
   
4. "work in the open" means work performed from open decks or in spaces from which the overhead has been completely removed;
   
   
5. "secured" means closed so as to avoid accidental opening or operation. 

Tanker Designation ^

"tank vessel" means any vessel especially constructed or converted to carry liquid bulk cargo in tanks; 

Vessel ^

"vessel" means any ship or boat or any other description of vessel used or designed to be used in navigation. 

Standard Safety Designations ^

7. These shall be used, where applicable, in preparing marine chemist's certificates, cargo tank labels and other references.

(1) "Safe for workers" means that in the compartment or space so designated:

1. the oxygen content of the atmosphere is at least 19.5 percent and not more than 23 percent by volume;
   
   
2. toxic materials in the atmosphere are within permissible concentrations; and
   
   
3. the residues cannot produce toxic materials under existing atmospheric conditions while maintained as directed on the marine chemist's certificate.

Note: For (b) and (c) above, refer to "Threshold Limit Values for Chemical Substances and Physical Agents", American Conference of Governmental Industrial Hygienists, P.O. Box 1937, Cincinnati, Ohio, 45201.

(2) "Not safe for workers" means that in the compartment or space so designated the requirements of ² safe for workers² have not been met.

(3) "Safe for hot work" means that in the compartment or space so designated,

1. the oxygen content of the atmosphere is at least 19.5 percent and not more than 23 percent by volume, except for inerted spaces or where external hot work is to be performed;
   
   
2. the concentration of flammable materials in the atmosphere is below 10 percent of the lower flammable limit;
   
   
3. the residues cannot produce a higher concentration than permitted by (b) under existing atmospheric conditions in the presence of fire and while maintained as directed on the marine chemist's certificate; and
   
   
4. all adjacent spaces containing, or having contained, flammable or combustible materials have been cleaned sufficiently to prevent the spread of fire; or are satisfactorily inerted; or, in the case of fuel tanks or lube oil tanks, or engine room or boiler room bilges, have been treated in accordance with the marine chemist's requirements.

(4) "Not safe for hot work" means that in the compartment so designated, the requirements of ² safe for hot work² have not been met.

(5) "Inerted" means that one of these procedures has been completed in the compartment or space so designated:

1. Carbon dioxide or other nonflammable gas acceptable to the marine chemist has been introduced into the space in sufficient volume to maintain the oxygen content of its atmosphere at or below 8.0 percent, or 50 percent of the amount required to support combustion, whichever is least.
   
   Note: The improper introduction of an inerting gas may generate sufficient static electricity for ignition.
   
   
2. The space has been flooded with water, provided that any hot work is performed at least 0.9 metres below the water level, that the gas content of the atmosphere above the water does not exceed 10 percent of the lower flammable limit, and that the procedure is approved by a marine chemist.
   
   
3. The marine chemist shall note, on the certificate, the kind of gas and the safe disposal or securing of gas inerting medium upon completion of repairs; closing and securing of hatches and other openings, except vents, may be considered as ² safe disposal² by the marine chemist.

(6) "Inerting for flammable compressed gas" means that individual tanks with a working pressure of 345 kPa or more are considered safe for work not directly involving these tanks or their pipelines when a positive pressure is maintained on the tanks by the flammable vapors remaining after the cargo has been discharged and special precautions are observed under carefully controlled conditions as specified on the marine chemist's certificate.

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