Part 9 Confined Spaces Lockout and Control of Harmful Substances9.18
9.18 Control of harmful substance in adjacent piping (3) Before a worker enters a confined space where adjacent piping contains a substance that is harmful only because of the temperature, pressure or quantity of the substance, the harmful substance must be controlled (a) by either disconnecting the adjacent piping or isolating it using blanks or blinds that meet the requirements of section 9.20 or using a double block and bleed system that meets the requirements of section 9.21,
9.18 Control of harmful substance in adjacent piping (b) by isolating the adjacent piping in a manner that a professional engineer has certified will make the confined space safe for a worker to carry out the intended work, or (c) if there is no head pressure in the adjacent piping, by de-energizing and locking out each pressure source for the adjacent piping and depressurizing the adjacent piping.
9.19 Isolation points (1) The employer must keep a record which identifies the location of every isolation point. (2) Every isolation point must be visually checked or otherwise verified to ensure that the confined space is effectively isolated before a worker enters the space.
Guideline - Interpretation Adjacent piping • "adjacent piping" means a device such as a pipe, line, duct or conduit which is connected to a confined space or is so located as to allow a substance from within the device to enter the confined space;
Guideline - Interpretation Two general types of adjacent piping. • A piping system that passes through the confined space: • not considered to be adjacent piping if it is designed and maintained so there are no openings or other locations in the piping where leakage may occur, and work on or around the piping will not cause leakage • If any work in the space may result in leakage, then the piping must be treated as adjacent piping
Guideline - Interpretation • Orifices between spaces: • adjacent spaces with one or more orifices in a common wall between them • an orifice in a wall between a confined space and another space is not adjacent piping. Blank, disconnect, double block and bleed, and blind requirements do not apply • ensure that workers are protected against any hazards associated with orifices • the potential for fluid discharge into the confined space must be controlled so that the hazards to workers are eliminated or minimized
Confined Space Confined Space Orifices Between Spaces Sluice gate Gate valve Butterfly valve Stop logs
Application of section 9.18(3) Materials hazardous only because of pressure, temperature, or quantityThis provision applies to materials that are not toxic or corrosive, and are harmful only because of pressure, temperature, or quantity. Typically this requirement applies to systems carrying water or steam. At present, sewerage is not included. See section 9.22
Application of section 9.18(3) Three isolation options are outlined in the Regulation. • Controls meeting the requirements of section 9.18(2): This alternative specifies the options of disconnecting, blanking, blinding, or a double block and bleed system.
Application of section 9.18(3) • Isolation per engineering certification (Section 9.18(3)(b)): This alternative enables an employer to have a professional engineer certify a means of isolation as making the confined space safe for a worker to carry out the intended work in the confined space.
Application of section 9.18(3) • De-energizing and locking out the pressure source: This control option applies if there is no head pressure in the adjacent piping (i.e., from neither gravity nor pumps). With this option, it is acceptable to de-energize and lock out each pressure source and depressurize the adjacent piping. For this option to apply, the layout of the adjacent piping has to be such that if all of the valves are opened with pumps locked out, fluid would not flow into the confined space. In such cases, locking out the pumps and depressurizing the line provides sufficient control.
Single Valve Isolation • The use of one or more valves as a means of isolation is not permitted except in certain specified cases for substances that are not volatile liquids, gases, or vapours or are harmful only because of pressure, temperature, or quantity • If a substance is corrosive, toxic, or has poor warning properties, then the use of valves as a means of isolation is not permitted.
Valves as Isolation The Regulation permits the use of valves as a means of isolation in the following two circumstances: • Where a double block and bleed system is permitted under section 9.18(2) and 9.18(3)(a) • Systems of isolation as permitted under section 9.18(3)(b).
9.18(3)(b) Certification of Isolation by a Professional Engineer WorkSafeBC recognizes that, for water (and steam), there are circumstances where it is impracticable to isolate the substance by disconnecting, blinding, blanking, or using double block and bleed technology, and this provides for an alternative manner of isolation.
9.18(3)(b) Certification of Isolation by a Professional Engineer Engineering certifications specifically need to address: • worker safety • amount of leakage • age • maintenance history of the piping components • any other means in place to make the confined space safe for a worker to carry out the intended work.
9.18(3)(b) Certification of Isolation by a Professional Engineer • Certifications are expected to be site specific and time limited, and the engineer will need to make the determination of the applicable time period as part of the certification process • Certifications need to be available for review by a WorkSafeBC prevention officer where necessary to assess compliance with the requirements
9.18(3)(b) Certification of Isolation by a Professional Engineer The system of isolation for public water supply systems may be one or more closed valves, use of inflatable bladders, or some other means of isolation. • The professional engineer must certify that the adjacent piping is isolated in a manner that makes it safe for a worker to carry out the intended work. • The engineer will need knowledge of the valves or other closure devices as well as the nature of the substance in the adjacent piping.
9.18(3)(b) Certification of Isolation by a Professional Engineer • A professional engineer may not always have sufficient information about a valve that is to be used to control potential flow into the confined space and may not be able to examine it. • In this case, the engineer could consider information such as the age, history, and maintenance records for the adjacent piping system, leakage rates, and measures such as leak control or line pressure reductions that can be accomplished etc.
9.18(3)(b) Certification of Isolation by a Professional Engineer • In this case, the engineer could consider information such as the age, history, and maintenance records for the adjacent piping system, leakage rates, and measures such as leak control or line pressure reductions that can be accomplished etc. • Metro Vancouver relies on information provided to the Engineer by field forces – signed off by the supervisor from the area
Certification of Isolation by a Professional Engineer *Bench tested prior to installation – the valve disks have been tested to the provided pressure rating. The valve body has been tested to double the provided pressure ratings. Data for each valve is tabulated
Certification of Isolation by a Professional Engineer Other wording, such as: In addition: • The valves above have been closed and the system has been drained since February 23, 2011. • Operation’s staff has determined there is no leakage from the valves and, • Operation’s staff will be monitoring the 150mm drain point at McKay and Maywood during the confined space entry.
Certification of Isolation by a Professional Engineer Based on the information provided above please have one of your Engineers complete the following to certify that the valves are safe to be used as single isolation for the scheduled confined space entry. I _____________________ have reviewed the information provided above and certify that the valves are adequate to be used as single isolation points and under these circumstances, it is safe for a worker to carry out the intended work. The engineering safety certification described within this document and executed herein shall be valid until April 8th, 2011. (signed) (dated) (sealed)