Download presentation
Presentation is loading. Please wait.
Published byReginald Bell Modified over 8 years ago
1
Rev. 1 © Chevron 2009 Confined Space Entry Awareness Plus
2
Rev. 1 © Chevron 2009 2 Training Objectives To explain what constitutes a confined space. To understand what controls should be in place when confined space entry is to be undertaken. To understand the requirements of a confined space attendant. To provide details on where additional information can be obtained.
3
Rev. 1 © Chevron 2009 3 Confined Space Definition Confined Space is any space that meets all of the following criteria: Is large enough and shaped so that a person can enter to perform assigned work; Has limited or restricted means of entry and exit; Is not designed for continuous human occupancy; Contains or has the potential to contain a hazardous atmosphere and could present a safety hazard
4
Rev. 1 © Chevron 2009 4 Confines Space – Basic Types Confined Spaces can be broken into two basic types: Open-topped enclosures with depths which a depth that can restrict the natural movement of air Whenever the depth is at or greater than 1.5 meters (5 feet) deep Examples: Oily water separators, pits, open-top floating roof tank, trenches, excavations, etc. Enclosures with limited opening for entry and exit Tanks, vessels, boilers, tanker truck trailers, rail cars, ducting, etc.
5
Rev. 1 © Chevron 2009 5 Confined Spaces The followings are some typical examples of confined spaces that may be found at a facility: Storage tanks or other type of vessels Tank truck compartment or rail tank cars. A floating roof whenever the roof is at 1.5m (5 ft.) or greater below the tank top rim Oily water separator’s chambers Sub pump pits Duct Work Drainage or other Sewer systems Excavations (when they are at 1.5 meters or greater in depth) Trenches (when they are at 1.5m or greater in depth)
6
Rev. 1 © Chevron 2009 6 Preparation for a Confined Space Entry Prior to entry into a confined space it must be properly prepared and assessed for entry. includes: Conducting a Hazards Assessment (Planning Phase) Developing an emergency Response plan. Positively Isolating the confined space, if it is a tank, vessel etc. Ventilating space (by natural ventilation or forced ventilation methods). Cleaning (e.g. Use of a vacuum system or air driven pump to remove residual product). Preparing signage and barricades.
7
Rev. 1 © Chevron 2009 7 Isolation of Confined Spaces All confined spaces to be entered shall be completely and positively isolated from all energy sources (e.g. product lines, steam lines, electrical circuits, etc.). Positive isolation of piping shall be at the closes flange to the vessel Positive Isolation must be done at the nearest connection (pipe flange, pipe spool, circuit breaker etc.) to the equipment or confined space.
8
Rev. 1 © Chevron 2009 8 Ventilation Where practicable all the man-ways of a vessel should be removed to increase ventilation. Forced ventilation should be started gradually just prior to initial removal of the first man-way to prevent pulling a vacuum Mechanical (forced) ventilation is normally quicker and safer than natural ventilation. Motors used on eductors or fans must be suitable for use in a hazardous area (use either air driven or if an electrical motor driven fan it must be explosion proof electrical equipment). Air movers and all ducting must be electrically bonded to the tank or vessel being vented to minimize the risk of a static discharge “sparking”.
9
Rev. 1 © Chevron 2009 9 Ventilation con’t Mechanical ventilation should not extract the air so fast as to create a vacuum inside the confined space. This is especially the case when the man-ways are still closed. Ensure vented vapors educted are being discharging to a safe area. Pure Oxygen should never be used to purge a confined space or to increase the oxygen level inside of a confined space. Gas Testing prior to entry into a confined space must ensure that there is sufficient oxygen. (Explosive meters (gas Testing Instruments) do not function properly in an oxygen deficient environment) There must be 16% to 20.8% Oxygen present to ensure % LEL is reading correctly.
10
Rev. 1 © Chevron 2009 10 Ventilation con’t Air discharging from ventilating equipment should wherever possible be discharged at a height where natural air currents can assist in the dispersion of the vapors. Venting in locations such as near communities and businesses may require: Vented vapors to be routed the through carbon scrubbers to eliminate noxious vapors, etc.
11
Rev. 1 © Chevron 2009 11 Conduct gas test readings to be taken in the following order: Oxygen (Oxygen 15% or higher to test for flammable vapors) Flammable vapors Toxic vapors Typical toxic vapors that can exist inside a confine space includes, but are not be limited to: Hydrogen sulfide (H2S) Benzene Carbon monoxide Carbon dioxide Continuous gas testing should be undertaken whenever personnel are performing work inside a confined space. Refer to Gas Detection Safety Bulletin for more information on gas testing. Gas Testing for Entry
12
Rev. 1 © Chevron 2009 12 Hazards Assessment is done in which phase of the work? Who should conduct the proposed job tasks hazard assessment? Confined Space Entry is to always be considered as a high risk job task and a Job Safety Analysis (JSA) or and equivalent process is required completed. The JSA must be reviewed and approved by the relevant facility’s management. The hazards Assessment should consider work that will be required to go on inside the confined space such as: Welding fumes, paint fumes, solvent vapors, oxidation (rust), oxygen consumption, etc.) Minimum PPE requirements must be identified. If entry requires personnel to use a respirator only personnel trained in their use and medically certified to use it can enter. Lighting requirements (e.g. explosion proof powered via a GFCB or use of low voltage lighting) Hazard Assessment
13
Rev. 1 © Chevron 2009 13 Hazards Risk Assessment (Planning Stage) Competent personnel must complete a risk assessment during the planning stage for entry into the confined space. The assessment must take into account the following: The nature of the confined space; Open top enclosures at a depth of 1.5 M (5 feet) or greater Equipment/vessels, etc with limited access for entry and exit The work required to be done, including it is necessary to enter the confined space; The range of methods by which the work can be done; The hazard involved and associated risks; Emergency and rescue procedures.
14
Rev. 1 © Chevron 2009 14 In addition to the hazards associated with the confined space, confined space entries can also involve the following additional hazards: Limited body movement (cramped conditions) High Temperatures (Heat Stress) Noise (High Decibels) Restricted (limited) vision Loose and or falling objects striking personnel Note: All of these additional factors can result in work taking longer than would normally be expected and must be considered during the planning phase of the confined space work. Additional Hazards
15
Rev. 1 © Chevron 2009 15 Entry with Supplied Breathing Air No Entry Entry is Allowed 19.5 % O2 23.5 % O2 16.5 % O2 No Entry Without Respiratory Protection if: LEL 0% Benzene < 0.5 ppm Hydrogen Sulfide < 5 ppm CO < 25 PPM Total Hydrocarbons < 300 ppm Temperature < 43.3 C (110 F) Providing: LEL < 10% Toxic vapours below their IDLH Temperature < 43.3 C (110 F) An Oxygen Enriched Atmosphere Exists Insufficient Oxygen to sustain life
16
Rev. 1 © Chevron 2009 16 An emergency plan must be developed before entry is allowed into a confined space. The emergency plan must be displayed at the work site, adjacent to the confined space. The plan must, as a minimum, detail the following: Procedures for reporting emergencies Notification of trained rescue personnel Rescue equipment to be available on site Emergency escape routes Procedures for authorized entrants to the space The designated emergency assembly area Rescue and first aid procedures and duties Emergency Action Plan
17
Rev. 1 © Chevron 2009 17 A trained Entry Watch (attendant) must always be present at the entry point of the confined space entry whenever people are entering or are inside. Additional Entry Watch (attendants) may be required under some circumstances. Confined Space Attendant
18
Rev. 1 © Chevron 2009 18 The Entry Watch attendants’ must be adequately trained in their duties and responsibilities, which includes: Control Entry into the confined space maintaining an entry & exit log Maintain contact with people inside the space. Clear the personnel from the confined space if the site conditions change or facility alarm sounds Raise the alarm if a problem occurs inside of the confine space Ensure gas testing results are within acceptable limits and properly taken at recorded as required by permit. Be aware to changing conditions that may present a hazard and clear the space if unsafe conditions arise. Confined Space Attendant
19
Rev. 1 © Chevron 2009 19 Confined Space – Additional Information For additional details on confined space entry requirements refer to: Your companies general operating procedures/standards/guidelines covering: General Work Hot Work Gas Testing Isolation Excavation Work at height Your Company’s Safety Officer
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.