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Guidelines for Uniform Temporary Marking of Underground Facilities
One-Call Systems -The One-Call damage prevention system shall be contacted prior to excavation.
Proposed Excavation - Use white marks to show the location, route or boundary of proposed excavation. Surface marks on roadways do not exceed 1.5" by 18" (40 mm by 450 mm).The facility color and facility owner identity may be added to white flags or stakes.
Use of Temporary Marking - Use color-coded surface marks (i.e., paint or chalk) to indicate the location or route of active and out-of-service buried lines. To increase visibility, color coded vertical markers (i.e., stakes or flags) should supplement surface marks. Marks and markers indicate the name, initials or logo of the company that owns or operates the line, and width of the facility if it is greater than 2" (50 mm). Marks placed by other than line owner/operator or its agent indicate the identity of the designating firm. Multiple lines in joint trench are marked in tandem. If the surface over the buried line is to be removed, supplementary offset markings are used. Offset markings are on a uniform alignment and clearly indicate the actual facility is a specific distance away.
Tolerance Zone - Any excavation within the tolerance zone is performed with non-powered hand tools or non-invasive method until the marked facility is exposed. The width of the tolerance zone may be specified in law or code. If not, a tolerance zone including the width of the facility plus 18” (450 mm) measured horizontally from each side of the facility is recommended.
Adopt Uniform Color Code -The APWA encourages public agencies, utilities, contractors, other associations, manufacturers and all others involved in excavation to adopt the APWA Uniform Color Code, using ANSI standard 2535.1 Safety Colors for temporary marking and facility ID.
Using the Table
Example: How many tons of gravel will be needed for an area that is 20' wide, 100' long to be 2" deep?
NOTE: Gravel can have different densities (weight)
NOTE: This table is based on the common "Aggregate" Weight of 100lbs per CF
Estimating Fill Material
NOTE: You must add a percentage to the excavated area to account for the "swell." The amount is based on the soil type.
Calculate the Swell Factor
Example: What is the total amount of soil to haul away if the excavation is 200 cubic yards of wet gravel?
NOTE: Swell factor has not been considered in this example.
Example: Calculate the CYs of Dirt to be removed from an excavation that is 20' by 35'. The soil type is A.
NOTE: Required Slopes are based on soil type and is regulated by OSHA. Before you calculate dirt to be excavated, you must identify the soil type and determine the required slope.
Example: This example shows an excavation with an average depth of 10'. A 1/2:1 slope means the excavation must be sloped 1/2 unit for each 1 unit of depth. For a 10' depth the slope will extend within 5' of the edge of the excavation. A 1:1 required slope with slope to 10' of the edge of where the average depth begins.
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