Safety Policy and Procedure

Transcription

1 Safety Policy and Procedure Policy Number 004 Authorized By: The Cianbro Companies Alan Burton Title: Excavation Safety Effective Date: 01/01/75 Page 1 of 16 1 Status 1.1 Update of existing policy, effective 06/03/11. 2 Purpose 2.1 This safety policy and procedure outlines planning considerations applying to all open excavations made in the earth's surface. Our primary objective is to prevent team member exposure to excavation hazards such as cave-ins, equipment or material that could fall/roll from an excavation face, and the collapse of adjacent structures. 3 Applicability 3.1 This policy applies to all subsidiary companies and departments of the Cianbro Companies. 3.2 All organizations are required to comply with the provisions of this policy and procedure. Any deviation, unless spelled out specifically in the policy, requires the permission of the Corporate Safety Officer or designee. 4 Definitions 4.1 Benching (Benching System): Method of protecting team members from cave-ins by excavating the sides of an excavation to form one or a series of horizontal levels or steps, usually with vertical or near-vertical surfaces between levels. 4.2 Cohesive Soil: Clay (fine grained soil), soil with high clay content, which has cohesive strength. Cohesive soil does not crumble, can be excavated with vertical side slopes, and is plastic when moist. Cohesive soil is hard to break up when dry and sticks together when submerged. Cohesive soils include clay silt, sandy clay, silty clay, clay and organic clay. 4.3 Competent Person: Capable of identifying existing and predictable hazards in the surroundings, or working conditions which are unsanitary, hazardous, or dangerous to team members, and who has authorization to take prompt corrective measures to eliminate them; must be experienced and knowledgeable in OSHA excavation standards. 4.4 Confined Space: A confined space is any space having limited means of egress, not normally team member occupied. This could be subject to accumulation of toxic or flammable contaminants or has an oxygen deficient atmosphere. Confined spaces include, but are not limited to, storage tanks, process vessels, bins, boilers, ventilation or exhaust ducts, sewers, underground utility vaults, tunnels, pipelines and open top spaces more than four (4) feet in depth such as excavations, pits, tubs, vaults and vessels. 4.5 Excavation: Any man-made cut, cavity, trench, or depression in an earth surface formed by earth removal. 4.6 Fissured: A soil material that has a tendency to break along definite planes of fracture with little resistance, or a material that exhibits open cracks, such as tension cracks in an exposed surface. Policy: 004 Excavation Safety Rev. 06/03/11 Page 1

2 4.7 Granular: Gravel, sand or silt (coarse-grained soil) with little or no clay content. Granular soil has no cohesive strength. Some moist granular soils exhibit apparent cohesion. Granular soil cannot be molded when moist and crumbles easily when dry. 4.8 Layered System: Two or more distinctively different soil or rock types arranged in layers. Seams or weakened planes in rock or shale are considered layered. 4.9 Stable Rock: Is a natural solid mineral matter that can be excavated with vertical sides and remain intact while exposed Submerged Soil: A soil that is underwater or is free seeping Type A Soil: Cohesive soils with an unconfined compressive strength of 1.5 ton per square foot (tsf) (144 KPa) or greater. Examples of cohesive soil or clay, silty clay, sandy clay, clay loam and, in some cases, silty clay loam and sandy clay loam. Cemented soils such as caliche and hardpan are also considered Type A. However, no soil is Type A if: The soil is fissured; or The soil is subject to vibration from heavy traffic, pile driving from heavy traffic, pile driving, or similar effects; or The soil had been previously disturbed; or The soil is part of a sloped, layered system where the layers dip into the excavation on a slope of four horizontal to one vertical (4H:1V) or greater; or The material is subject to other to other factors that would require it to be classified as a less stable material Type B Soil: Cohesive soil with an unconfined compressive strength greater that 0.5 tsf (48 kpa) but less than 1.5 tsf (144 kpa); or Granular cohesionless soils including: angular gravel (similar to crushed rock), silt, silt loam, sandy loam and, in some cases, silty clay loam and sandy clay loam. Previously disturbed soils except those, which would otherwise be classed as Type C soil. Soil that meets the unconfined compressive strength or cementation requirements for Type A, but is fissured or subject to vibration; or Dry rock that is not stable; or Material that is part of a sloped, layered system where the layers dip into the excavation on a slope less steep than four horizontal to one vertical (4H:1V), but only if the material would otherwise be classified as Type B Type C Soil: Cohesive soil with and unconfined compressive strength of 0.5 tsf (48 kpa) or less; or Granular soils including gravel, sand, and loamy sand: or Submerged soil or soil from which water is freely seeping: or Submerged rock that is not stable, or Material in a sloped, layered system where the layers dip into the excavation or slope of four horizontal to one vertical (4H:1V) or steeper 5 Policy 5.1 Team members and subcontractors working around excavations will be protected from cave-ins and other excavation related hazards. All excavation work will meet the requirements of this policy and of 29 CFR 1926 Subpart P Excavations. 6 Responsibilities 6.1 The top Cianbro manager of the job site is responsible for the implementation of this policy on the project. 6.2 Corporate Safety is responsible for maintaining this document. Policy: 004 Excavation Safety Rev. 06/03/11 Page 2

3 7 Excavation Safety Index 7.1 Site Evaluation and Activity Planning Exemptions from Excavation Protection Systems Requirements Soil Classifications Sloping/Benching and Shielding/Shoring Options Call Before You Dig Law Safety at Home Related Documents Appendix A Maximum Allowable Slopes Appendix B Subpart P Selection of Protective Systems Site Evaluation and Activity Planning Prior to starting any excavations, the location of underground installations must be determined and the site must be checked by a competent person for other potential hazards. Reference below and excavation planning checklist found on Cianbro.net. A Cianbro competent person shall meet OSHA s definition of a competent person, plus be knowledgeable of the OSHA excavation/trenching standards, Cianbro s excavation Safety Policy and Procedure and have successfully demonstrated such experience. Cianbro s job site management teams have the responsibility to determine which of our team members meet the requirements of a competent person on their site. The competent person must conduct inspections of all excavations and document the results daily. Check for electrical power lines (overhead and buried), natural gas and water lines and all other installations. Contact the utility company(s) and call Dig Safe in your area. The number for Dig Safe in ME, NH, VT, MA, and RI is DIG-SAFE. See page 6 of this Safety Policy and Procedure for other state contact numbers. If, after following the Dig Safe requirements and contacting the utility companies, the exact location of the underground installations is not established, we may proceed with extreme caution provided detection equipment or other acceptable means to locate the utility installations are used. Testing should be conducted for air contaminants (oxygen levels, flammable gases, etc.) and ventilation should be provided where necessary. The soil should also be tested for possible contaminants and hazardous materials. Potential falls greater than 6 feet. Excavations greater than four (4) feet deep shall be considered a confined space, which requires following Cianbro s Confined Space Entry Safety Policy and Procedure. Included in this safety policy and procedure is a requirement for air monitoring for air quality Develop a written activity plan using the checklist provided in this safety policy and procedure as guidance. 7.2 Exemptions from Excavation Protection Systems Requirements There are two situations where protective systems are not required: If the excavation is made entirely in "stable rock". If the excavation is less than five (5) feet in depth and examination by a competent person provides no indication of a potential cave in. 7.3 Soil Classifications Soils are classified into four (4) types: NATURAL solid mineral material (rock) Type A soil Type B soil Type C soil Policy: 004 Excavation Safety Rev. 06/03/11 Page 3

4 7.3.2 VISUAL AND MANUAL TESTS should be conducted as specified in OSHA regulations to determine soil type However, most soil conditions we encounter are worst case type C. If we follow the maximum allowable limits specified (table B-1.3 attached) for sloping, benching, shielding or shoring then VISUAL and MANUAL tests are not necessary. NOTE: If it is not possible to follow table B-1.3 in performing your excavation activities, refer to OSHA subpart P for soil class descriptions and visual and manual test guidelines. 7.4 Sloping/Benching and Shielding/Shoring Options Maximum allowable OSHA limits for sloping require an angle not steeper than one and a half (1 1/2) horizontal to one (1) vertical [34 (thirty-four degrees)]. This 34 sloping is normally used for protection in type C soils. Cianbro typically treats the soil as Type C Lesser slopes and benching are allowed but require visual and manual soil type identification and are allowed only in Type A and B soil. Competent persons can conduct soil testing Other protection systems (shielding/shoring) require approval and/or designs by a registered professional engineer. Trench boxes require you to have the manufacturer s engineering data on site. 7.5 Call Before You Dig Law Each state has its own versions of the law that requires an excavator to call the local One Call agency (Dig Safe, Dig Safely, Miss Utility) three business days (add another day for major holidays) prior to the start of any excavation on public or private land. Failure to comply establishes legal negligence on the part of the excavator and is subject to a fine (up to $5000 per violation) along with liability for all damages and injuries that may ensue. Specifically the law requires: Premark the excavation area in white paint. Include the name or initials of your company. Call the local One Call agency (See below for contact information) three business days prior to start of excavation and they will issue a reference number that indicates you have complied with the law. If you have not pre-marked the area a V will be prefixed to your reference number indicating that you are already in violation. Contact any utility that is not a member of the One Call agency. Wait 72 hours before excavation begins (3 business days). This waiting period can be waived by the One Call agency only in emergencies. The excavator must maintain the locates by some appropriate means. If the marks are lost, re-notify the One Call agency. If a line is damaged, disturbed, or if the lines were improperly marked you must report it. The One Call agency permits are usually valid for 30 days and you must re-notify at day 27 to avoid waiting additional hours to continue. This does not replace excavation permits that are currently required by local ordinances. Do not assume that owners and subcontractors are in compliance with the law but instead make certain that the One Call agency is notified. Policy: 004 Excavation Safety Rev. 06/03/11 Page 4

5 We can avoid violations of the law by following the Cianbro Excavation Safety Policy and Procedure in the generation of the Activity Plan. Before you call the One Call agency and as a part of the Activity Plan, be prepared to provide the following information. Request No. Time: Date: State: Municipality: Location: Intersecting Street: Type of Work: Name of Caller: Title: Start Date: Time: Phone Number: Best Call Back Time: Company: Notified: Remarks: Excavator Doing Work: Local One Call Agency Contact Numbers: Connecticut New Jersey Delaware New York D.C., Maryland New York City Pennsylvania Virginia West Virginia Virginia/Delmarva Maine, Massachusetts, New Hampshire, Rhode Island, Vermont 888-DIG-SAFE ( ) For a list of all state One Call numbers go to: Note: In those cases where the inspections state agency will not go onto private property, Cianbro project management must coordinate closely with the host/owner to determine locations of underground encumbrances. There are also private companies that will do underground location on private sites. See for a list of private locating companies. Note: Project Designers (architects, engineers, etc.) must call area utilities themselves to locate lines (not the One Call agency) and include the location of the lines on the plans. Connecticut Delaware DC Maine Maryland Massachusetts New Hampshire New York Pennsylvania Rhode Island Vermont Virginia West Virginia More information can be obtained on the web at: (Delmarva Peninsula) gy%2c+utilities+%26+clean+technologies&l2=water+distribution+%26 %2345%3B+Investor-Owned+Utilities&L3=Dig+Safe&sid=Eoeea Policy: 004 Excavation Safety Rev. 06/03/11 Page 5

6 7.6 Safety at Home Fill in with excavation safety information that pertains to at home use. 8 Budget / Approval Process 8.1 It is the responsibility of each jobsite to procure and provide all materials and PPE required and provide necessary training. 9 Related Documents 9.1 See attachments. 9.2 Documents available on Cianbro.net Trenching & Excavation Daily Checklist Excavation Planning Checklist SD1060 SD1064 Policy: 004 Excavation Safety Rev. 06/03/11 Page 6

7 9.1 Appendix A Maximum Allowable Slopes Table B-1 Maximum Allowable Slopes SOIL OR ROCK TYPE MAXIMUM ALLOWABLE SLOPES (H:V) FOR EXCAVATIONS LESS THAN 200 FEET DEEP (3) STABLE ROCK VERTICAL (90 ) TYPE A (2) ¾:1 (53 ) TYPE B 1:1 (45 ) TYPE C 1 ½:1 (34 ) NOTES: 1. Numbers shown in parentheses next to maximu allowable slopes are angles expressed in degrees from the horizontal. Angles have been rounded off. 2. A short-term (open less than 24 hours) maximum allowable slope of 1/2H:1V (63 ) is allowed in excavations in Type A soil that are 12 feet (3.67 M) or less in depth. Short-term maximum allowable slopes for excavations greater than 12 feet (3.67 M) in depth shall be 3/4h:1V (53 ). 3. Sloping or benching for excavations greater than 20 feet deep shall be designed by a registered professional engineer. Figure B-Slope Configurations (All slopes stated below are in the horizontal to vertical ratio) B-1.1 Excavations made in Type A soil. All simple slope excavation 20 feet or less in depth shall have a maximum allowable slope of ¾ to 1. Simple Slope General Exception: Simple slope excavations, which are open 24 hours or less (short-term) and which are 12 feet or less in depth shall have a maximum allowable slope of ½:1. Policy: 004 Excavation Safety Rev. 06/03/11 Page 7

8 Simple Slope Short Term All benched excavation 20 feet or less in depth shall have a maximum allowable slope of ¾ to 1 and maximum bench dimensions as follows: Simple Bench Multiple Bench All excavations 8 feet or less in depth which have unsupported vertically sided lower portions shall have a maximum vertical side of 3 ½ feet. Policy: 004 Excavation Safety Rev. 06/03/11 Page 8

9 Unsupported Vertically Sided Lower Portion Maximum 8 Feet in Depth All excavations more than 8 feet but not more than 12 feet in depth which unsupported more than 8 feet but not more than 12 feet in depth which unsupported vertically sided lower portions shall have a maximum allowable slope of 1:1 and a maximum vertical side of 3 ½ feet. Unsupported Vertically Sided Lower Portion Maximum 12 feet in Depth All excavations 20 feet or less in depth which have vertically sided lower portions that are supported or shielded shall have a maximum allowable slope of ¾:1. The support or shield system must extend at least 18 inches above the top of the vertical side. Supported of Shielded Vertically Sided Lower Portion All other simple slope, compound slope, and vertically sided lower portion excavations shall be in accordance with the other permitted under (b). Policy: 004 Excavation Safety Rev. 06/03/11 Page 9

10 B-1.2 Excavations Made in Type B Soil All simple slope excavations 20 feet or less in depth shall have a maximum allowable slope of 1:1. Shown below. Simple Slope All benched excavations 20 feet or less in depth shall have a maximum allowable slope of 1:1 and maximum bench dimension as follows: This bench allowed in cohesive soil only. Shown below. Single Bench This bench allowed in cohesive soil only. Shown below. Multiple Bench All excavations 20 feet or less in depth which have vertically sided lower portions shall be shielded or supported to a height at least 18 inches above the top of the vertical side. All such excavations shall have a maximum allowable slope of 1:1. Policy: 004 Excavation Safety Rev. 06/03/11 Page 10

11 Vertically Sided Lower Portion All other sloped excavations shall be in accordance with the other options permitted in (b). B-1.3 Excavations Made in Type C Soil All simple slope excavations 20 feet or less in depth shall have a maximum allowable slope of 1 ½:1. Simple Slope All excavation 20 feet or less in depth which have vertically sided lower portions shall be shielded or supported to a height at least 18 inches above the top of the vertical side. All such excavations shall have a maximum allowable slope of 1 ½:1. Vertical Sided Lower Portion All other sloped excavations shall be in accordance with the other options permitted in (b). Policy: 004 Excavation Safety Rev. 06/03/11 Page 11

12 B-1.4 Excavations Made in Layered Soils All excavations 20 feet or less in depth made in layered soils shall have a maximum allowable slope for each layer as set forth below. A OVER B A OVER C B OVER C All other sloped excavations shall be in accordance with the other options permitted in (b). Policy: 004 Excavation Safety Rev. 06/03/11 Page 12

13 B OVER A C OVER A C OVER B Policy: 004 Excavation Safety Rev. 06/03/11 Page 13

14 9.2 Appendix B Subpart P Selection of Protective Systems Subpart P Selection of Protective Systems The following figures are a graphic summary of the requirements contained in subpart P for excavations 20 feet or less in depth. Protective systems for use in excavations more than 20 feet in depth must be designed by a registered professional engineer in accordance with (b) and (c). Is the excavation more than 5 feet in depth? Is there potential for cave-in? NO YES Is the excavation entirely in stable rock? NO Excavation may be made with vertical sides. YES YES Excavation must be sloped, shored, or shielded. NO Sloping selected. Shoring or shielding selected. Go to Figure 2 Go to Figure 3 FIGURE 1 PRELIMINARY DECISIONS Policy: 004 Excavation Safety Rev. 06/03/11 Page 14

15 Sloping selected as the method of protection Will soil classification be made in accordance with (b)? YES NO Excavation must comply with one of the following three options: Excavations must comply with (b) (1) which requires a slope of 1 1/2H:1V (34 ). Option 1: (b) (2) that requires Appendices A and B to be followed. Option 2: (b) (3) that requires other tabulated data (see definition) to be followed. Option 3: (b) (4) that requires the excavation to be designed by a registered professional engineer. FIGURE 2 SLOPING OPTIONS Policy: 004 Excavation Safety Rev. 06/03/11 Page 15

16 Shoring or shielding selected as the method or protection. Soil classification is required when shoring or shielding is used. The excavation must comply with one of the following four options: Option 1: (c) (1) that requires Appendices A OPES / SLOPE CONFIGUS and C to be followed (e.g. timber shoring). Option 2: (c) (2) that requires manufacturers data to be followed (e.g. hydraulic shorting, trench jacks, air shores, shields). Option 3: (c) (3) that requires tabulated data (see definition) to be followed (e.g. any system as per the tabulated data). Option 4: (c) (4) that requires the excavation to be designed by a registered professional engineer (e.g. any designed system). FIGURE 3 SHORING AND SHORING OPTIONS Policy: 004 Excavation Safety Rev. 06/03/11 Page 16