1、 Method For Calculating An Estimated Weight-Per-Foot of Solid-Wall Plastic Pipe TR- 7 2014 2 Foreword METHOD FOR CALCULATING AN ESTIMATED WEIGHT-PER-FOOT OF SOLID-WALL PLASTIC PIPE This report was developed and published with the technical help and financial support of the members of the Plastics Pi
2、pe Institute, Inc. (PPI). The members have shown their interest in quality products by assisting independent standard-making and user organizations in the development of standards, and also by developing reports on an industry-wide basis to help engineers, code officials, specifying groups, and user
3、s. The purpose of this technical report is to provide engineers, users, contractors, code officials, and other interested parties with a standard method for calculating an estimated, nominal weight-per-foot of solid wall plastic pipe. This method uses nominal average outside diameter and average wal
4、l thickness dimensions. Depending on the pipe manufacturing standard and production equipment used, the actual pipe weight may vary from the weight-per-foot determined by using this method. This Technical Report does not establish specifications, or standards, for pipe weight-per-foot. It is intende
5、d to provide general information for use in estimating pipe weight-per-foot. The pipe manufacturer should be consulted for their estimated pipe weight-per-foot. PPI has prepared this report as a service to the industry. The information in this report is offered in good faith and believed to be accur
6、ate at the time of its preparation, but is offered “as is” without any express or implied warranty, including WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Additional information may be needed in some areas, especially with regard to unusual or special applications. Consult the
7、 manufacturer or material supplier for more detailed information. A listing of member manufacturers is available from PPI. PPI does not endorse the proprietary products or processes of any manufacturer, and assumes no responsibility for compliance with applicable laws and regulations. PPI intends to
8、 revise this report from time to time, in response to comments and suggestions from users of the report. Please send suggestions of improvements to: The Plastics Pipe Institute, Inc. www.plasticpipe.org This Technical Report, TR-7, was first issued in March 1968 and was revised in September 1988, Ma
9、y 2000, April 2007, and November 2014. 3 METHOD FOR CALCULATING AN ESTIMATED WEIGHT-PER-FOOT for SOLID-WALL PLASTIC PIPE 1.0 INTRODUCTION This Technical Report 7 describes a method for estimating the weight-per- foot for solid wall plastic pipe and tubing. This report does not set specifications, or
10、 standards, for product weights. The estimated value can vary from production pipe weight per foot because actual product will vary from the average dimension and density values assumed within the method. 2.0 SIGNIFICANCE 2.1 TR-7 provides a standard method for calculating an estimated weight-per-fo
11、ot of plastic pipe and tubing. The estimated weight-per-foot may be useful for project design, sales, shipping, and handling purposes Use of this method provides information that is meaningful in commercial practice, benefiting both the consumer and the plastic pipe industry. 2.2 The TR-7 method use
12、s the density, in gm/cm3 at 73Fof the plastic pipe material compound, an average pipe outside diameter, an average pipe wall thickness, all in inches, to estimate pipe weight in pounds per foot. Depending upon the industry specification, pipe and tubing dimensions can vary; therefore, the user is st
13、rongly cautioned to obtain and review the pertinent product specifications. The pipe or tubing manufacturer should be consulted for the density of its plastic pipe compound (virgin resin plus pigment). In lieu of specific data, the density may be determined by testing per ASTM D792 or ASTM D1505. 3.
14、0 DEFINITIONS 3.1 Weight-Per Foot (W) - The solid wall pipe or tubing weight-per-foot, in pounds per foot, calculated using the material density, the average inside or outside diameter, and the average wall thickness, and rounded to three decimals for tubing and two decimal places for pipe. 3.2 Spec
15、ific Gravity (SG23 ) - The specific gravity of the pigmented plastic pipe material compound at 23oC, rounded to three decimal places. Note: Do not use the SG of the un- pigmented base resin. The density at 23C of the pigmented plastic pipe compound in grams per cubic centimeters divided by the densi
16、ty at 23C of water at 1.0 grams per cubic centimeter equals the specific gravity, which is dimensionless. 4 3.3 Average Outside Diameter (OD) ,or Average Inside Diameter (ID) : The outside diameter or inside diameter value, in inches rounded to three decimal places, obtained from the applicable pipe
17、 standard, plus, if applicable, half of the total diameter tolerance. If the diameter is specified as a minimum (maximum) value plus (or minus) a total tolerance, the average diameter is the minimum (maximum) value plus (or minus) half the total tolerance. If the diameter is specified as a value wit
18、h a plus-or-minus tolerance, the average diameter is the specified value. 3.4 Average Wall Thickness ( t ) : The wall thickness value, in inches rounded to three decimal places, obtained from the applicable pipe standard, plus, if applicable, half the total wall thickness tolerance. If the wall thic
19、kness is specified as a minimum value plus a total tolerance, the average wall thickness equals the sum of the minimum value plus half the total tolerance. If the wall thickness is specified as a value with a plus-or-minus tolerance, the average wall thickness is the specified value. Note : For larg
20、e diameter extruded thermoplastic pipe, some specifications require a minimum wall thickness and a maximum percent eccentricity, but do not specify a maximum wall thickness. For convenience, 106% of the minimum wall thickness is used as an average wall thickness in this method. However, the actual a
21、verage wall thickness can be greater. For example, if the thinnest wall measured is 2% greater than the specified minimum wall thickness, +12% eccentricity would allow the maximum wall thickness to be 14% above minimum wall thickness. For this example, the resultant average wall thickness value calc
22、ulates to be 107% of the minimum wall thickness. 4.0 FORMULAE 4.1 Formulae for estimating the nominal weight-per-foot of solid wall plastic pipe, in pounds per foot, are given as follows; the derivation is presented in the Appendix: W = SG23 x (OD2 ID2) x 0.34049 Eq. #1 4.2 When the pipe dimensions
23、are designated by outside diameter and wall thickness, equation #1 simplifies to: W = SG23 x (OD tavg) x tavg x 1.36196 Eq. #2 4.3 When the tube or pipe dimensions are designated by inside diameter and wall thickness, equation #1 simplifies to: W = SG23 x (ID + tavg) x tavg x 1.36196 Eq. #3 5 5.0 Ex
24、ample Calculation: 5.1 Calculate the weight per foot of High Density Polyethylene Pipe with an average outside diameter of 2.375 inches of DR 11 with a wall tolerance of +12%, with Specific Gravity, at 23C, of 0.955 . 5.1.1 Determine the average wall thickness, tavg : tmin = ODnominal/ DR = 2.375/11
25、= 0.216 inches tavg = tmin x (1 + (0.12/2) = tmin x 1.06 = 0.216” x 1.06 = 0.229 inches 5.1.2 Determine the average weight per foot : W = 0.955 x (2.375 0.229) x 0.229 x 1.36196 = 0.639 lbs/ft 6.0 Report 6.1 The report should include the following : (a) Complete identification of the material from w
26、hich the pipe is made. (b) The Specific Gravity at 73F (23C), of the material, to three decimal places (i.e.: 0.955). (c) The dimensions and tolerances of the pipe, and the standard or specification from which these dimensions and tolerances were taken. (d) The Weight-per-Foot, rounded to at least t
27、wo decimal places. (Note: For tubing diameters, rounding to three or more places is advisable.) 6 Appendix Derivation of Weight-per-Foot Formula These formulae use English units of inches, pounds, and feet. W = SG23 x Pi/4 x (OD2 ID2) x 1 foot x12 in/ft x 62.4lb/ft3 x (1 / 1728 in3/ft3) W = SG23 x (OD2 ID2) x 0.34049 = _ lbs / ft. Note : (OD2 ID2) = 4 x ( OD tavg) x tavg Therefore W = SG23 x (OD tavg) x tavg x 1.36196 = _ lbs / ft.
