CITY AND COUNTY OF BROOMFIELD Wastewater Division Confined Space Entry Policy

Transcription

1 CITY AND COUNTY OF BROOMFIELD Wastewater Division Confined Space Entry Policy PURPOSE: To ensure a safe and secure work environment through the use of OSHA confined space entry principles at Wastewater Division confined spaces. SCOPE: This policy applies to all individuals including but not limited to, City and County employees, City and County officials, City and County volunteers, contractual / sub-contractual workers, authorized visitors, authorized vendors, etc. STATEMENTS OF POLICY: Confined Space Entry Each Wastewater Division building will have a site-specific confined space entry policy that will be placed into the Wastewater Division Employee Handbook. WWRF confined space locations, classifications and descriptions are as follows: LOCATION / CATEGORY Ops. & Maint. Building. / Class C BRIEF DESCRIPTION FeCl 3 Feed Vault Screwpump Discharge Wetwell East & West Grit Chambers Primary Clarifier Scum Pit Primary Clarifier Sump Pump Vault Headworks Building / Class C Water Spray Manhole (for Bio-Filter) Generator Building / Class C 6 x 26 Electrical Vault DAF Building / Class A TWAS Vault (Pit Chamber) DAF Building / Class A Chopper Pump Vault DAF Building / Class C Water Line Vault (manhole) Digester # 1 Building / Class C Electrical Vault NE corner) Digester # 1 Building / Class C MCC Room Electrical Vault (subbasement) Digester Units 1-3 / Class D Anaerobic Digestion Reactors Grounds Maintenance Building / Class C Sub-basement DAF Lift Station / Class B Pump Vault Equalization Basin Building / Class A EQ Wetwell Equalization Basin Building / Class C Return Pump Manifold Vault Equalization Basin Building / Class C Return Valve Vault (outside) Equalization Basin Building / Class C By-Pass Vault (outside) Equalization Basin Building / Class A DAF Overflow Vault (outside) Non-Potable Water Building / Class C Sub-basement No. 1 Secondary Clarifier / Class A Effluent Junction Vault

2 RAS / WAS Building / Class A Raw Influent IJB Structure / Class A Sump Pump Vault (in basement) Inter-Junction Box (Influent Mix Chamber) The site-specific policy includes: Definitions of Relevant Terms Confined Spaces Confined Space - an accessible area with at least one of three characteristics: a limited number of openings for entry and egress, unfavorable natural ventilation, and/or designed only for limited worker occupancy. Limited Entry / Egress - limited for entry and exit primarily by size and/or location. Small openings may obstruct the entry or egress of equipment, especially personal protective equipment (PPE). Examples of PPE include respirators needed for 0 2 -deficient atmospheres, and life-saving or rescue equipment. Access to top-opened spaces may require the use of ladders, hoists or other devices that could impede a rapid or safe escape from the confined space during an emergency situation. Unfavorable Ventilation - Because natural air may not freely enter or travel a confined space due to its design, the atmosphere inside a confined space can differ greatly from that outside the space. Deadly toxic fumes or flammable gases may be trapped inside, particularly if the confined space is used to store or to process industrial chemicals or wastewater bio-solid sludges. Oxygen inside a confined space may not be sufficient to support life (< 19.5% O 2 by volume), OR might be O 2 excessive (>23.5% O 2 by volume) which will increase the risk of either combustion or explosion if an ignition source is present. Non-continuous Occupancy Most confined spaces are not designed for routine or continuous occupancy. Therefore infrequent worker entry is difficult and dangerous due to either physical or chemical hazards within the confined space. Low Hazard and High Hazard Confined Spaces Low Hazard Spaces - permit-required confined spaces where there has been an evaluation determined that an extremely low likelihood exists of an IDLH (Immediately Dangerous to Life and Health) or engulfment atmosphere present and where any and all other injurious or lethal hazards have been eliminated. High Hazard Spaces where there is an IDLH or engulfment hazard present. Any employee entering such a space will wear a Self-Contained Breathing Apparatus (SCBA) along with atmospheric monitoring equipment. No employee shall enter an area such as this without at least one attendant and one site

3 supervisor present. A lifeline that is NIOSH-approved will be attached to the entrant throughout the event. The attendant will attend the lifeline and tripod, as well as maintain communication with the entrant(s). Any exceptions to this rule will be noted on the entry Permit. Confined Space Categories All Permit / Non-Permit confined spaces shall be classified into one of the following categories: Class A - a confined space that is either above or below grade (ground / floor level) that is difficult to access, has no built-in gas detection and monitoring device(s), can harbor either toxic or explosive gases, or possess an oxygendeficient atmosphere. Class B - a confined space that is either above or below grade, that is quite easily accessed either by steps or through a door, is well ventilated but also has the risk of hazardous gases within it. Class C - a confined space that is either above or below grade, that is NOT easily accessed has no danger of toxic or explosive gases present, and has no possibility of an oxygen-deficient atmosphere. Class D - a confined space that is either above or below grade, and is known to contain either toxic or explosive gases that require special precautions as well as specific written procedures for entry and egress. Potential Hazards associated with Confined Space Entry The following atmospheric conditions must be considered before a confined space entry event is executed: Oxygen Deficiency - if the oxygen content in the confined space is tested as being below 19.5%, do NOT enter that confined space without using a Self- Contained Breathing Apparatus (SCBA). Flammable or Explosive Atmospheres - A close-by ignition source such as a spark or an open flame need to be eradicated before a confined space entry event. Toxic substances and contaminants gases and vapors which contain toxic and/or medically hazardous contaminants, even if they are not flammable or combustible. Chemicals used for cleaning or equipment maintenance may accumulate to a toxic level or create an oxygen deficiency.

4 Mechanical and Structural Conditions Potential safety issues related to structural and mechanical conditions include: Limited Confined Space Entry and Egress Time Restricted Bodily Movement Limited visibility and physical barriers to communication Possibility of Entrapment and Engulfment Slick or Wet Surfaces - could increase the likelihood of electrical shock where tools and other equipment, as well as electrical circuits and conduits, are located. Falling Objects - workers must recognize and be constantly vigilant to the possibility of falling tools and equipment, particularly in confined spaces with a top-side entry opening, or confined spaces that have more than one level, story or floor in them. Traffic Control - ensure that all motor vehicle emissions are clearly away from the entrance to a confined space, especially manholes and other below-grade entries. Noise and Temperature Extremes - a confined space can easily amplify noise due to its design and acoustical materials, and could impair even a shouting warning. It may also harbor extremes in hot or cold air temperatures, adversely affecting the ability of worker(s) to perform work safely or indefinitely. Site Security and Personal Protective Equipment - monitoring a confined space for security can be hampered by the configuration of the space itself, as well as cause the use of PPE to be restricted or even jeopardized as regards safety. Responsibilities for Entry into, as well as Work inside, Confined Spaces Training training modules must consist of (at a minimum) Hazard Recognition, Respiratory Protection, Personal Protective Equipment and Rescue Procedures Confined Space Entry Permits a copy of the completed Permit must be posted immediately adjacent to the space while work is in progress. No person shall enter the space without the permit being properly completed and signed off by the Site Supervisor. There must be an attendant present before the event is executed. Confined Space Entry Permit Contents:

5 1) The exact identity of the confined space 2) The exact purpose of the confined space event 3) Date and time of the Entry event 4) Duration of authorization a permit may be valid for up to one full year, so as all conditions under which the permit was issued remains valid. 5) List of all authorized entrants 6) List of all qualified and eligible attendants 7) Communication procedures to be used between attendant and entrant(s) 8) The signature and printed name of the authorizing Site Supervisor 9) A list of the suspected or known hazards of the confined space. 10) Isolation of Space - safety cones, barricades, safety fencing, etc. 11) Hazard Controls - lockout/tagout, gas purge ventilation, fluid pumpout 12)Environmental Maintenance explosion-proof hardhat lighting, tripod lighting, constant air purge, continuous gas and O 2 monitoring, etc. 13) Listing of rescue / emergency services, with means of contacting them 14) Rescue equipment provided on-site at Broomfield Wastewater facility 15) Required personal protective equipment used during the actual event Atmospheric Monitoring Confined Space Entry - entry into a confined space is prohibited until initial testing of the atmosphere inside the confined space has been completed from the outside. Appropriate tests for oxygen deficiency, excessive oxygen levels, flammability and combustibility, LEL and UEL of toxic and hazardous gases should be made by use of an approved gas detection unit. Monitoring will continue until event is completed. HOT WORK entry into a confined space for any type of hot work or work that has an ignition source. Only metal grinding is performed by WWRF staff in a confined space; any arc welding, oxyacetylene brazing and cutting, and gas water welding is performed in a work area away from any confined spaces. Tests must indicate that the internal atmosphere must be at a level below 5% of the LEL (lower explosive limit) before hot work may be performed in any confined space. As has been discussed before in this policy, it is necessary to perform continuous O 2 and other atmospheric monitoring for the duration of hot work. If hot work is to be authorized for a permitted confined space, then this information must be noted very prominently on the confined space entry permit. Equipment instruments and other equipment used for continuous atmospheric monitoring shall be intrinsically safe and equipped with either an audible alarm or a danger-signaling device which can alert employees to a hazardous condition.

6 Any instruments used for air monitoring a confined space will be able to measure four major categories of concern: 1) Hydrogen sulfide (H 2 S) - no greater than 5ppm on measurement 2) Oxygen gas (O 2 ) - no less than 19.5% (deficiency) 3) Oxygen gas (O 2 ) - no more than 23.5% (flammable excess) 4) Methane gas (CH 4 ) - no greater than 1% of the lower explosive limit (LEL) as listed in CDC/NIOSH Guide 5) All Combustible - no greater than 5% of the lower explosive Gas of Vapors limit (LEL) as listed in CDC/NIOSH Guide VENTILATION when the atmosphere of confined space is questionable, purging is the required procedure in adjusting the atmosphere to an acceptable level. Purge the ventilation blower for a minimum of one (1) minute above grade before placing it into the confined space. Purge ventilation rates at an absolute minimum of one (1) minute per each foot of hosing depth, with a minimum vent hose length of three (3) to five (5) feet from any invert. Purge for a minimum of five (5) minutes before re-testing so that continuous monitoring can be maintained throughout the event. Special precautions need to be taken for any opening that involves partial blocking, from methods of maintaining communication to methods of providing respirable air to each entrant for the time necessary to egress (exit) the confined space. Other Issues Related to Confined Space Entry Lighting - explosion-proof lighting that is MSHA-approved shall be used to provide illumination when working in any confined space. Broomfield Wastewater Division personnel will be equipped with approved lighting for lockon attachment to hardhats, alleviating any need to preoccupy either hand during work. Medical - it is highly recommended that a WWRF staffperson be available (during a confined space entry event) who is currently certified in both first-aid procedures and cardio-pulmonary resuscitation (CPR). All WWRF personnel will receive annual training in both first-aid and CPR.

7 Administrative Scope prior to opening or entering any permit-classified confined space, all entrants shall comply with the requirements of the Permit checklist and Permit associated with the particular space to be entered. Any violations of the Wastewater Division Confined Space Policy will be subject to disciplinary action.