ISSUE: DS 2011-085. Petitioner seeks a Declaratory Statement on an interpretation of Sections R4101.6.1 and R4101.6.3 of the Florida  Building Code, Residential, 403.9 of the Florida Building Code, Energy Conservation, and industry standards  NSPI-5, APSP-7 and APSP-15 as referenced by the code.

 

Petitioner in DS 2011-085 seeks clarification of the following questions:

1.      Does a pool contractor achieve compliance with NSPI-5 and R4101.6.3 by applying the design flow rate when specifying pipe sizes?

2.      Does a pool contractor achieve compliance with ANSI/APSP/ICC-15 by applying the maximum design flow rate when specifying swimming pool filtration pipe sizes, where the maximum design flow rate is the greater of the calculated 6-hour turnover flow rate or the optional auxiliary feature (spa) with the highest design flow requirement if operated by the circulations pump?

3.      Does a pool contractor achieve compliance with ANSI/APSP-7 by applying the maximum operational flow rate when specifying suction pipe sizes?

 

Mr. Dan Johnson of Swim, Incorporated, is designing a residential pool in Bradenton, Florida, in accordance with the 2010 Florida Building Code. It is a 10,700 gallon pool with a therapy spa.

 

Proponent believes that a pool contractor must achieve compliance separately for each standard. If the separate velocity requirements are misinterpreted, project costs will escalate,  placing an unreasonable financial burden on the average pool buying family and seriously shrinking the market to a point where numbers of pool building contractors would likely go out of business. 

 

 Background:

 

2010 Florida Building Code:

 

1.      Sections R4101.6.1 and R4101.6.3 of the 2010 Florida Building Code, Residential, read as follows:

R4101.6.1, Conformance standard.  Design, construction and workmanship shall be in conformity with the requirements of ANSI/NSPI 3; ANSI/NSPI 4; ANSI/NSPA 5; ANSI/NSPI 6; and ANSI/APSP 7.

R4101.6.3, Water velocity. Pool piping shall be designed so the water velocity will not exceed 10 feet per second (3048 mm/s) for pressure piping and 8 feet per second (2438 mm/s) for suction piping, except that the water velocity shall not exceed 8 feet per second (2438 mm/s) in copper tubing. Main suction outlet velocity must comply with ANSI/APSP 7.

 Exception: Jet inlet fittings shall not be deemed subject to this requirement.

  1. Section 403.9 of the 2010 Florida Building Code, Energy Conservation, reads (in part) as follows:  

403.9 Swimming pools, inground spas, and portable spas (Mandatory). The energy requirements for residential pools and inground spas shall be as specified in Sections 403.9.1 through 403.9.4 and ANSI/APSP-15. The energy requirements for portable spas shall be in accordance with Section 403.9.5 and ANSI/APSP-14.

403.9.4 Residential pool pumps and pump motors. Pool filtration pump motors shall meet the following requirements:

1.  Pool pump motors shall not be split-phase, shaded-pole or capacitor start-induction run types.

2.  Pool pumps and pool pump motors with a total horsepower (HP) of ≥ 1 HP shall have the capability of operating at two or more speeds. The low speed shall have a rotation rate of no more than ½ of the motor’s maximum rotation rate.

3.  Pool pumps motor controls shall have the capability of operating the pool pump at a minimum of two speeds. The default circulation speed shall be the residential filtration speed, with a higher speed override capability for a temporary period not to exceed one normal cycle or 24 hours, whichever is less.

Exception:  Solar pool heating systems shall be permitted to run at higher speeds during periods of usable solar heat gain. 

 

 

  1. The three industry standards and their respective flow and velocity requirements are:

 

    1. ANSI/NSPI-5, 2003    Standard for Inground Residential Swimming Pools

           

The objective of this standard is to provide recommended minimum guidelines for the design, equipment, installation, and use of residential inground swimming pools. Maximum velocity limits are: 10 feet per second (fps) in return side piping and 8 fps in suction side piping. The flow and velocity requirements in this standard are intended to insure adequate water flow for sanitation, filtration, filter backwashing, etc. Maximum system flow is not defined in this standard; the flow requirement is that the equipment shall be sized to provide a turnover of the pool water at least once every twelve (12) hours.          

 

 

b.      ANSI/APSP 7-, 2006      Standard for Suction Entrapment Avoidance in Swimming Pools, Wading Pools, Spas, Hot Tubs and Catch Basins.

 

The objective of this standard is to provide recommended minimum guidelines for suction entrapment avoidance in the design, equipment, operation and installation of new and existing swimming pools, wading pools, spas, hot tubs and catch basins for builders, installers, pool operators and service professionals Maximum water velocity limits are: in branch suction piping (piping between dual or multiple outlets) shall be limited to 6 feet per second when one of a pair is blocked. All other suction piping velocities shall be 8 fps for residential pools. This standard does not address return side velocities. The flow and velocity limits in this standard are intended to prevent suction entrapment. I quote “This standard was written to move performance criteria for each identified hazard and allow state authorities to define clear codes for use by designers, builders and inspectors”. Maximum system flow rate is defined as “The flow resulting from the lowest possible total dynamic head (TDH) for a circulation system.

 

c.       ANSI/APSP/ICC-15, 2011      Standard for Residential Swimming Pool and Spa Energy Efficiency

 

The objective of this newly adopted conformance standard is to provide recommended minimum guidelines for the energy efficiency of permanently installed residential aboveground/onground and inground swimming pools and inground spas Maximum water velocity limits are 8 fps in return piping and 6 fps in suction line piping. Maximum filtration flow rate is defined in this standard as “the flow rate needed to turn over the pool water volume in 6 hours (pool volume in gallons ÷ 360 = gpm) or a flow rate of 36 gpm, whichever is greater”. Maximum system flow rate is defined in this standard as “the maximum flow rate for the auxiliary pool loads (a spa for example) or the filtration flow rate, whichever is greater.”  The maximum flow rate for pools without optional auxiliary loads is determined by a mathematical calculation based on pool volume divided by size hours – not the maximum potential flow and/or velocity as defined in the ANSI/APSP-7, 2006 standard. The intent of the ANSI-15 standard is most clear when evaluating a swimming pool system without optional auxiliary pool loads, a situation where pipe size is determined exclusively by the calculation pool volume in gallons ÷ 360 = maximum flow rate in gpm.

 

 

Staff Recommendations:  Based on the above facts and circumstances, staff provides the following recommendations as answers to proponent’s questions:

Question 1:

To the question, Does a pool contractor achieve compliance with NSPI-5 and R4101.6.3 by applying the design flow rate when specifying pipe sizes? As per the project in question, the answer is “yes”.

 

Question 2:

To the question, Does a pool contractor achieve compliance with ANSI/APSP/ICC-15 by applying the maximum design flow rate when specifying swimming pool filtration pipe sizes, where the maximum design flow rate is the greater of the calculated 6-hour turnover flow rate or the optional auxiliary feature (spa) with the highest design flow requirement if operated by the circulations pump?, As per the project in question, the answer is “yes”.

 

Question 3: 

To the question, Does a pool contractor achieve compliance with ANSI/APSP-7 by applying the maximum operational flow rate when specifying suction pipe sizes?, As per the project in question, the answer is “yes”.