Technical Report

Karl Caouette, CPD
V.P. Technical
April 2019

The meeting last month that was about drinking fountains and water filling stations. We learned how bottle fillers help conserve energy and help reduce waste. In addition to water conservation, Mr. Mitch Whittington also went into discussing the environmental benefits of drinking water solutions and bottle filling stations and how they compare to existing technologies.

IAPMO/UPC 2018 CODE CHANGES

What Changed.
A 104.4 Developed Length. Determine the developed length of pipe from the water (street) main to the highest fixture. Where close estimates are desired, compute with the aid of Table A 104.4(1), Table A 104.4(2), or Table A 104.4(3), whichever is applicable, the equivalent length of pipe for fittings in the line from the water (street) main to the highest fixture and add the sum to the developed length. The pressure available for friction loss in psi (kPa), divided by the developed lengths of pipe from the water (street) main to the highest fixture, times 100, will be the average permissible friction loss per 100 feet (30 480 mm) length of pipe.

A 105.0 Size of Building Supply.

A 105.1 Diameter. Knowing the permissible friction loss per 100 feet (30 480 mm) of pipe and the total demand, the diameter of the building supply pipe shall be permitted to be obtained from Chart A 105.1(1), Chart A 105.1(2), Chart A 105.1(3), or Chart A 105.1(4), Chart A 105.1(5), Chart A 105.1(6), or Chart A 105.1(7), whichever is applicable. The diameter of pipe on or next above the coordinate point corresponding to the estimated total demand and the permissible friction loss will be the size needed up to the first branch from the building supply pipe.

Why It Changed.
This change adds CPVC and PVC information to Appendix A to assist user when sizing a CPVC or PVC system. Table A 104.4(2) information came from the Specification Sheet: Chlorinated Polyvinyl Chloride (CPVC) Plastic Pipe and Fittings for Hot and Cold Water Distribution Systems published by Plastic Pipe and Fittings Association (PPFA).

The change is for CPVC of CTS (Copper Tube Size), Schedule 40 and 80 and PVC of Schedule 40 and 80. Chart A 105.1(5), Chart A 105.1(6), and Chart A 105.1(7) came from IAPMO IS-20, and Plastic in the header was removed and CPVC and/or PVC was added.

PEX data was requested but the industry could not provide the same information due to the variability of the designs for those piping system fittings. The change added Ferrous Pipe to the headers for Charts A 105.1(2)A ,105.1(3) and A 105.1(4) and CPVC and PVC to the proposed additional Charts to make it clear as to which pipe was covered in each chart.

What It Means to Me.
The purpose for determining the developed length of pipe from the street main to the most distant fixture is to derive the average permissible friction loss per 100 feet of pipe length for ferrous metal, non-ferrous metal, CPVC or PVC piping materials. Begin by laying out a sketch of the building water supply system from the street main and determine the following:

  1. The developed length of the building main (indicated by W in Figure A 104.4);
  2. The developed length from the street main to the foot of each riser branching from the building main (the three separate sections of W in Figure A 104.4);
  3. The greatest developed length of pipe from the street main to the top of any riser. In Figure A 104.4, there are three risers from the building main. Determine the developed length for each riser.
  4. Table 104.4 provides equivalent lengths of pipe for the various fittings and valves. When a close estimate is required, compute the equivalent length of pipe for all fittings in each developed length of pipe and add the sum to the developed length.

Calculating the Permissible Friction Loss in Pounds per Square Inch per 100 Feet.

The following summarizes the steps needed to derive the permissible friction loss in order to determine the diameter of the building supply, branches and risers.

  1. Start with the minimum daily service pressure.
  2. Subtract from the minimum daily service pressure:
    1. Friction loss due to the water meter, water treatment devices, and backflow devices.
    2. The residual pressure required at the highest fixture, or the fixture or appliance that has the highest total pressure drop.
    3. The static pressure when it is a loss (add to the service pressure when it is a gain).
  3. Divide the resulting pressure available for friction loss by the greatest developed length in feet. This will yield the average permissible friction loss per foot of pipe. Multiply the result by 100. This will yield the average permissible friction loss per 100 feet of pipe and will be useful when applied to the friction loss charts to calculate velocity and pipe diameter. The use of the friction loss charts is explained in Section A 105.1.

Knowing the supply demand load (gpm) and the allowable friction loss per 100 feet (in psi), the building supply, risers, and the various branches can be determined.

Engineers and designers need to be aware that, when using Appendix A, Recommended Rules for Sizing theWater Supply System, if they choose to specify CPVC or PVC for a water service material, they must use the appropriate table to verify the total developed length and friction loss to determine the total demand and diameter of the water service pipe.

Plans examiners and inspectors shall verify the plans, specifications meet the requirements of Appendix A and inspectors must verify the pipe material and size is the same as the approved plans.

The plumbers, installers or technicians must have the experience and training to know if the CPVC and PVC water services they are installing meet the minimum requirements of Appendix A and the 2018 UPC.

Our April 6 topic will be about “Fire Sprinkler Systems” presented by Mr. Gregg Vlahakis of Viking Corporation. During the presentation, Mr. Vlahakis will be discussing fire sprinkler systems related to project type and specific approval requirements. Mr. Vlahakis will also go into discussing wet, dry, preaction, and regulating flow options. This will be a topic that you don’t want to miss!!!

If anyone has any future topic requests or suggestions, please email me at karl.caouette@hendersonengineers.com.