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Code adoption update – Earlier this month, the Washington State Building Code Council agreed to delay the effective date of the 2021 construction codes to March 15, 2024. Adoption of the 2021 City of Seattle codes will follow sometime after.
Prohibited fittings and practices – Plumbing Contractors involved with the installation of stainless steel domestic water systems please take note: Any time a fitting (weld-o-let, thread-o-let, flange, etc,), multiple fittings, or a fitting and a section of pipe are welded together, that final assembly is considered a ‘fitting’ by definition and is required to be Listed before being installed in any domestic water distribution system. This does not apply to ‘welded joints’ between a pipe and manufactured fitting, or multiple pipe sections. However, it does apply if multiple pipe sections are arranged such that cutting into the side of a pipe is required to create the finished assembly (i.e. a fabricated tee or wye). We are aware of only one local contractor that has gone through the process of listing their fabricated fittings to both NSF 61 and IAPMO PS 53. Unlisted fittings are prohibited and will be flagged during inspections. We will provide a more detailed article on this issue in an upcoming newsletter.
Venting systems presentation links – Many who have attended one of Steve Hart’s presentations on UPC venting systems have asked if the presentation was available for distribution. Unfortunately, due to IP and copyright law, they are not. However, there are slightly older versions of these presentations available to the public through the IAPMO website:
Policy update – Historically, King County Plumbing & Gas has had an informal allowance for up to (3) water heater T&P relief lines to be combined before terminating to an Approved location. In an ongoing effort to be transparent and equitable, and to provide better clarity to the industry, we have decided to discontinue this allowance. Enforcement will now be in strict accordance with UPC/SPC Section 608.5.
New Design Guidance posted – After much collaboration with our industry partners, we have developed a new and reformatted version of our general Commercial Plumbing Design Guidance document. This document outlines what information is expected to be provided on a set of plumbing plans submitted for plan review. We are working on a revision that will allow a smaller AHJ Approval stamp box and hope to publish that update shortly.
Sample plans coming – Our next guidance development goal is to create a basic set of sample plans for public reference. This will include a typical cover sheet, calculations, schedules, plans, risers, and details. The goal is to provide a visual example of what we are asking for in our Design Guidance document to avoid confusion and streamline the plan review process.
Future guidance – High on our list of next priorities are guidance documents related to commercial kitchen design, backflow prevention, lab plumbing, and updating some of our other more outdated guidance documents (water reuse systems, medical gas, etc.). If you have suggestions on what matters most to you and your firm, please send an email to planreviewinfo@kingcounty.gov and let us know!
By Duane Jonlin, Energy Code and Energy Conservation Advisor, Seattle Department of Construction and Inspections
The 2018 Washington State and Seattle energy codes will remain in force until sometime in early 2024. The delay is giving state and local code officials time to modify the code in response to a recent California court decision. Meanwhile, we’ve heard a lot of questions from applicants about heat pump water heater (HPWH) requirements in the code, so here’s a quick summary.
What’s in the 2018 Codes?
The 2018 Washington State Energy Code does not require heat pump water heating (or heat pump anything, for that matter). So outside of Seattle, there’s no heat pump requirement (although you might check the federal websites to see if you qualify for any incentives).
In the 2018 Seattle Commercial Energy Code, heat pumps are required in several situations:
- New hotel and multifamily (R-1 and R-2 occupancy) buildings with central service water heating systems. (“Central systems” do not include individual in-unit water heaters.) See Section C404.2.3 in the Seattle code.
- Any other new building that either has a hot water circulation system or has a total of more than 15 kW (51 kBTU/h) water heating capacity under the same permit. You can find these requirements in a separate City Council action at: Seattle SDCI - 2018 Seattle Energy Code Amendment, Heat Pump Scope Change.
- There are several exceptions:
- Up to 15 kW of water heating in a tenant space that’s built out under a separate permit (separate from other spaces) can be electric resistance.
- Instantaneous electric water heaters serving fixtures up to 8 feet away can be electric resistance.
- Solar thermal, ground-source heat pump, or systems using waste heat.
- Systems meeting the NEEA Advanced Water Heating Specification for central service water heating systems.
- Unitary electric HPWH located in conditioned space, sized so that it doesn’t use supplementary electric resistance water heating.
- Occupancies other than hotel and multifamily served by existing district steam systems.
- Booster heaters for commercial dishwashers and food service equipment.
- Alterations to existing buildings. Replacement central service water heating equipment in existing hotel and multifamily buildings must be heat pumps, with one important exception:
- One piece of failing water heating equipment can be replaced like-for-like with gas or electric resistance equipment, if no other work on the system is involved and this exception hasn’t been used in the previous two years.
- For all other occupancies, replacement service water heating equipment can use gas or electric resistance.
What’s planned for the “2021” Codes?
The 2021 Washington State Commercial Energy Code, planned to take effect in early 2024, includes requirements for heat pump water heating similar to Seattle’s 2018 code requirements.
New buildings, both residential and commercial, must use air-source (or ground-source) heat pump water heaters. Of the ten exceptions, a few of the most commonly used include:
- Small systems. You can use electric resistance water heating if the total water heating capacity in your building or project is no greater than 24 kW plus 0.1 watts per square foot.
- Example 1: A 10,000 sf building would be permitted 24,000 + (0.1 x 10,000) = 25,000 watts = 25 kW of electric resistance water heating.
- Example 2: A 100,000 sf building would be permitted 24,000 + (0.1 x 100,000) = 34,000 watts = 34 kW of electric resistance water heating.
- Emergency backup systems for institutional buildings like hospitals or correctional buildings can be gas or electric resistance.
The 2021 Seattle Energy Code has almost the same requirements, with a few additional exceptions:
- Instantaneous water heaters. You can install local point of use instantaneous electric water heaters serving nearby fixtures. These don’t have to be added to the 0.1W/sf limit for the small systems exception.
- Unitary heat pump water heaters. You can install unitary (all-in-one) electric heat pump water heaters in conditioned spaces, if they’re sized to operate without supplementary electric resistance heat.
- Standby equipment, only used when the primary equipment is not available, can be electric resistance.
Sizing your heat pump
Heat pumps are less efficient in colder temperatures, so some systems may require supplementary electric resistance heating for very cold days.
For Seattle projects: Size your HPWH system capacity to be large enough to provide all the required water heating using the heat pump’s compressor when the surrounding air is 40°F and large enough to provide at least half of the required water heating with the compressor when the surrounding air is 24°F. Any supplemental heating must be electric, not gas, with smaller capacity than the heat pump operating at 40°.
Elsewhere in Washington state: Size your HPWH system capacity to be large enough to provide half of the required water heating using the heat pump’s compressor when the surrounding air is 40°F and large enough to provide at least 25% of the required water heating with the compressor when the surrounding air is 24°F. Either gas or electric resistance is permitted for supplemental heating with smaller capacity than the heat pump operating at 40°.
In each case, the HPWH capacity must also accommodate defrost cycles, as recommended by the manufacturer. Some HPWH types, particularly those using CO2 refrigerant, maintain high efficiency in temperatures far below freezing and do not require supplementary heat, so the electric service to the HPWH can be smaller.
Use a system sizing tool approved by SDCI or a sizing recommendation provided by the manufacturer of the HPWH equipment you are using. One free online tool for sizing multifamily central water heating systems is called Ecosizer, available at https://ecosizer.ecotope.com/sizer/.
Supplemental water heating
Supplemental electric resistance water heating is permitted under several conditions, including:
- Temperature maintenance for reheating the water in the circulating loop.
- Compressor coil defrost.
- Heat trace of piping.
- Supplemental heating when incoming air temperature is below 40°F, provided that the heat pump compressor continues to operate down to 24°F.
- Supplemental heat downstream from a multi-pass HPWH system.
- Stand-alone water heaters serving single zones and not served by the circulating loop.
Commissioning
Water heating systems larger than 200,000 BTU/h system capacity require commissioning. System capacity is defined as the capacity of the primary heat pumps only, at 40°F outside air temperature.
Metering
Water heating systems with electrical demand larger than 50 kVA require end-use submetering. The 50 kVA threshold includes the total power to the heat pumps.
How about single-family houses and townhouses?
The current 2018 residential energy code does not require HPWHs. The “2021” code does require HPWHs for new single-family and townhouse construction. Size the HPWH to generate all of its peak hot water demand with the compressor (not using electric resistance) when the air temperature around the HPWH is above 40°F. There are several exceptions, including:
- Small (less than 20 gallon) electric water heaters
- Small (less than 1,000 square foot) dwellings
- Water heating by solar thermal or waste heat recovery systems
Potential “Fossil Fuel Compliance Pathway”
A recent federal court decision in a California case has put the 2021 State and Seattle implementations on hold, while each code works out revised code language to comply with that court interpretation. Most likely there will be an alternate code compliance path that allows gas heating and water heating equipment, together with the substantial building efficiency upgrades that would be required to make a building with gas heating and water heating equipment be just as efficient as a building with heat pumps.
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