Staff Analysis for Declaratory Statement Request DS2018-066

Issue DS 2018-018. Petitioner seeks clarification of the following question:

Question: Does section R403.5.1 state that all single family dwellings MUST install hot water recirculating systems or does R403.5.1 state that IF a hot water recirculating system is installed in a single family dwelling, it then MUST conform to the control systems stipulated in section R403.5.1?

Background:

The Petitioner, David Porter AIA of David Porter Associates Architects Inc., seeks a declaratory statement concerning interpretation of R403.5, R403.5.1, and R403.5.1.1. Specifically an interpretation is requested concerning the installation of hot water recirculating systems, and whether they are mandatory.

Project: The Petitioner is designing an 850 square foot house for Habitat for Humanity. The tank-style water heater is very close to the plumbing fixtures. Petitioner states that the hot water from the tank to the fixtures will be near instantaneous. The petitioner feels that a recirculating system is unwarranted in this instance.

6^th Edition (2017) Florida Building Code, Energy Conservation

R403.5 Service hot water systems. Energy conservation measures for service hot water systems shall be in accordance with Sections R403.5.1 through R403.5.6.

R403.5.1 Heated water circulation and temperature maintenance systems (Mandatory). Heated water circulation systems shall be in accordance with Section R403.5.1.1. Heat trace temperature maintenance systems shall be in accordance with Section R403.5.1.2. Automatic controls, temperature sensors and pumps shall be accessible. Manual controls shall be readily accessible.

R403.5.1.1 Circulation systems. Heated water circulation systems shall be provided with a circulation pump. The system return pipe shall be a dedicated return pipe or a cold water supply pipe. Gravity and thermo- syphon circulation systems shall be prohibited. Controls for circulating hot water system pumps shall start the pump based on the identification of a demand for hot water within the occupancy. The controls shall automatically turn off the pump when the water in the circulation loop is at the desired temperature and when there is no demand for hot water.

R403.5.1.2 Heat trace systems. Electric heat trace systems shall comply with IEEE 515.1 or UL 515. Controls for such systems shall automatically adjust the energy input to the heat tracing to maintain the desired water temperature in the piping in accordance with the times when heated water is used in the occupancy.

SECTION R202 GENERAL DEFINITIONS

SERVICE WATER HEATING. Supply of hot water for purposes other than comfort heating.

2015 International Energy Conservation Code Commentary

Commentary:

When the distribution piping is heated to maintain

usage temperatures, such as in circulating hot water

systems or systems using pipe heating cable, the

system pump or heat trace cable must have conveniently

located manual or automatic switches or other

controls that can be set to optimize system operation

or turn off the system during periods of reduced

demand. The simplest of these devices is an automatic

time clock. Notice, however, that the code will

accept either a readily accessible manual switch or

an automatic means to turn off the circulating pump.

Staff Analysis:

To the question, “does section R403.5.1 state that all single family dwelling Must install hot water recirculating systems?” The answer is “No.” The requirements of Section R403.5.1 of the 6^th Edition (2017) Florida Building Code (FBC), Energy Conservation do not apply to the project in question. This section is mandatory if a heated water circulation system is installed.

To the question, “does R403.5.1 state that IF a hot water recirculating system is installed in a single family dwelling, it then MUST conform to the control systems stipulated in section R403.5.1?” The answer is “Yes.” The requirements of Section R403.5.1 of the FBC, Energy Conservation are mandatory for a heated water circulation system.