Calculating the Specific Gravity (SG) of a substance is easy. It is the ratio of the density of a substance to the density of water,

The formula is SG = d (density of the substance)/ d (density of water). But, while calculating the SG of a substance only requires using the formula, finding the weight of FRP piping and contents is more difficult. However, you can use this chart of typical FRP piping and contents to estimate the total per lineal foot. The estimated total weights are provided for various values of specific gravity of contents. Keep in mind that, since FRP properties and dimensions can vary significantly, this information should only be used for preliminary estimates. It is the piping design engineer’s responsibility to confirm all spans.