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DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 04-007 Revised
  • Date: June 5, 2007
  • Subject: 3-Compartment (Restaurant) Sinks
  • Code / Section: 2003 UPC Table 7-3, Chapter 8

Decision. A three compartment sink may be installed with a continuous waste and a single trap. The continuous waste and trap shall not be smaller than the outlet/tailpiece. In this configuration, the 3 compartment sink will be considered as one fixture. Where each compartment is separately trapped and vented, each compartment (or trap) shall be considered a fixture. The size of the trap shall be the determining factor in applying Table 7-3 for fixture unit loadings.

Background. Clarification is necessary for consistent application of the drainage provisions and the permitting requirements for these types of sinks. The 2000 IAPMO UPC Interpretations Committee issued the following interpretation: "A three compartment commercial sink is rated at three drainage fixture units and the minimum size trap is one and one half inch. The size of the trap determines the rate of flow from a fixture to the drainage system and a three compartment sink may be installed with one trap. A multiple compartment fixture imposes additional loading on the plumbing system only if its individual compartments are separately connected to the waste and vent system."

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 04-005 Revised
  • Date: June 5, 2007
  • Subject: Access for Hot Water Tanks
  • Code / Section: UPC Chapter 5

Decision. The installation of a washer and/or dryer that obstructs the access requirements for a hot water tank is allowed where the following conditions are met:

  1. A shut off valve for the water supply shall be installed adjacent to the location of the water heater in an accessible location. The valve shall be identified; and
  2. A shut off valve for the gas supply shall be installed adjacent to the location of the water heater in an accessible location. The valve shall be identified. This shut off valve may be in addition to the individual equipment shut off valve required by Section 409.5 of the International Fuel Gas Code.

Background. A water heater must be accessible for inspection, repair or replacement. In some cases, such as with condominium conversions, a stacked-type washer and dryer unit may be located in front of a water heater, thus necessitating their being removed in order to access the water heater. This would not be a violation of the access requirements. However, should the water heater need to be shut down due to a malfunction, access to the water and gas supply should be accessible without having to move other appliances.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 04-006 Revised
  • Date: July 18, 2008
  • Subject: Air Admittance Valves
  • Code / Section: Chapter 9 - Venting

Decision. Air admittance valves (AAV) are approved for use subject to the following conditions:

  1. General. Individual- and branch-type AAV's shall conform to ASSE 1051.

  2. Installation. AAV's shall be installed in accordance with the requirements of this policy and the manufacturer's installation instructions. The AAV shall be rated in accordance with the standard for the size of vent to which the valve is connected. AAV's shall be installed after the drain, waste and vent testing required in Section 712.0 of the Uniform Plumbing Code.

  3. Where permitted. Individual and branch vents shall be permitted to terminate with a connection to an AAV. AAV's shall only vent fixtures that are on the same floor level and connect to a horizontal branch drain.

  4. Relief vent. A relief vent is not required on horizontal branch drains which connect to the drainage stack or building drain within four (4) branch intervals (stories) from the top of the stack. All other horizontal branch drains shall be provided with a relief vent that shall extend outdoors to the open air or shall connect to a vent stack or stack vent that terminates outdoors to the open air. The relief vent shall connect to the horizontal branch drain between the stack or building drain and the most downstream fixture drain connected to the horizontal branch drain. The relief vent shall be at least ½ the diameter of the drain served, but in no case less that 1 ¼-inch in diameter, and shall be installed in accordance with Section 905.0 of the Uniform Plumbing Code and the length limitations of Table 7-5 of the Uniform Plumbing Code. The relief vent shall be permitted to serve as a vent for other fixtures. (See #9 below)

  5. Location. The AAV shall be located a minimum of four (4) inches above the branch drain or trap arm being vented. The AAV shall be located within the maximum developed length permitted for the vent in accordance with Table 7-5 of the Uniform Plumbing Code. The AAV shall be installed a minimum of six (6) inches above insulation material.

  6. Access and ventilation. Access shall be provided to all AAV's. The valve shall be located within a ventilated space that allows air to enter the valve. For the purpose of this approval, the space within a bathroom type or kitchen type cabinet with access doors shall be constituted a ventilated space.

  7. Aggregate cross-sectional area venting required. The use of AAV's does not exempt compliance with the aggregate cross-sectional area venting provisions of the Uniform Plumbing Code.

  8. Prohibited installations. AAV's shall not be installed in nonneutralized special waste systems as described in Chapter 8 of the Uniform Plumbing Code unless specifically approved for such use by the manufacturer. AAV's shall not be located in spaces utilized as supply or return air plenums. AAV's shall not be used for venting a sump or ejector pump without written approval of the AAV manufacturer.

  9. Prior approval required. Installations that require relief vents are subject to prior approval. A review of drawings may be required at the discretion of the Chief Plumbing Inspector or Senior Plumbing Inspector.

Background.  This policy conforms to Section 917 of the 2003 International Plumbing Code and has been modified to meet the intent of Chapter 9 of the 2003 Uniform Plumbing Code. This approval supercedes any previous approvals by Seattle/King County Public Health.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Date: January 12, 2009
  • Subject: Barrier Type Floor Drain Trap Seal Protection Devices
  • File No.: 09-001

Public Health - Seattle & King County does hereby approve for use within its jurisdiction the following product/method:
Barrier type floor drain trap seal protection devices listed as conforming to the ASSE 1072 product standard.

Description:
This product fits into a floor drain that comply with ANSI/ASME A112.6.3 to provide a barrier type method to prevent evaporation of the trap contents and the escape of gases, while providing appropriate drainage of discharges received.

Comments:
Since this barrier method does not automatically or periodically provide water to replenish the trap seal, it is designed to provide a barrier on the inlet side of the trap seal that minimizes evaporation, while at the same time providing adequate drainage capabilities required for the floor drain's intended use. The performance requirements of the product standard require tests of the device that take into consideration certain adverse conditions, such as fouling substances (dirt, sand, grease, floor wax, etc.) and both infrequent and unusually sizable discharges. (See additional inspection guidelines below.)

Approval is subject to the following conditions:

  • The device shall conform to ASSE 1072.
  • The product shall be installed in accordance with the manufacturer's installation instructions.
  • The product shall only be installed in a floor drain complying with ANSI/ASME A112.6.3.

Approval is hereby granted under the provisions of section(s):
2006 Uniform Plumbing Code, Section 301.2 - Alternate Materials and Methods Equivalency.


Additional information

The following information is included to assist during the inspection process. Table 2 of ASSE Standard #1072-2007 is included below and shows the various designations for installation in certain environments. The marking requirements of products conforming to the standard are also shown below.

Application Designation Test 3.1 Test 3.2 Test 3.3 Test 3.4 Test 3.5 Test 3.6 Test 3.7 Test 3.8 Test 3.9
Any floor finish AF  
Any floor,
Grease Laden Waste
AF-GW
Shower Floor SF    
Concrete Floor CF    
Ceramic Tile Floor CT    
Wood Floor WF  

Tests are as follows:

  • 3.1 - Flowiest
  • 3.2 - Evaporation Test
  • 3.3 - Trap Seal Interference Test
  • 3.4 - Opening Test
  • 3.5 - Dirt and Debris Test
  • 3.6 - Floor Wax Test
  • 3.7 - Grease Test
  • 3.8 - Life Cycle Test
  • 3.9 - Physical Test of Membrane Material

Requirements of ASSE 1072 for marking of devices and installation instructions.

Each device shall have the following information marked on it by a permanent method where it will be visible:

  1. Name of manufacturer or trademark.
  2. Application designation (per Table 2)

Each device shall have the following information marked on the packaging:

  1. Name of manufacturer or trademark.
  2. Model number or description of the device.
  3. Rating for type of floor.
  4. Rated for grease-laden waste, if applicable.
  5. Floor drain size.

Instructions for installation of the device shall be on the packaging or packaged with the device.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 10-002 Revised
  • Date: October 5, 2010
  • Subject: Chemical Dispenser Installation and Backflow Protection
  • Code / Section: 2009 UPC Chapter 14, Section

Decision. Potable water outlets with hose attachments shall be protected in accordance with Section 603.4.7. There shall be no shutoff downstream of the backflow preventer, except (1) where a chemical dispenser conforming to ASSE 1055 B is installed in accordance with the manufacturer's installation instructions, or (2) where a water wasting tee (also referred to as a pressure indicating tee) is installed on the hose threads of the faucet.

Background. Chemical dispensers confo1ming to ASSE 1055 meet the backflow requirements of the UPC. This standard applies to those devices classified as chemical dispensing systems having a self-contained means of backflow protection. The devices are classified as follows:

  • Type A. These devices have the chemical(s) pressurized above atmospheric pressure and connect directly to the water system.

  • Type B. These devices connect to the hose threads of a faucet and do not pressurize the chemical(s) above atmospheric pressure. The only source of back pressure comes from an elevated hose.

Either of these types can include shutoff valves. Since the unit itself contains the appropriate backflow protection, the outlet it connects to would not require additional protection. However, because Type B chemical dispensers connect to hose-threaded outlets and can easily be removed and replaced, backflow protection of the hose-threaded outlet shall be provided in accordance with the plumbing code, typically by means of a vacuum breaker equipped faucet, or by means of either an ASSE 1011 hose-connection vacuum breaker or an ASSE 1052 hose-connection backflow preventer installed on the hose-thread outlet of the faucet.

Where a non-listed/approved chemical dispenser is installed downstream of the protected hose-threaded outlet, there shall not be a shutoff downstream of the backflow prevention device, except where a water wasting tee (also referred to as a pressure indicating tee) can be properly installed on the hose threads of the faucet. This device acts the same as a kitchen faucet with a hos·e spray attachment where the faucet must be in the "on" position in order to use the hose spray, and when the hose spray lever is released the faucet will discharge from the spout. In this way the hose spray can never cause a pressure build-up into the potable water system and would break any siphoning action in the event of a loss of pressure in the water distribution system.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 04-010
  • Date: October 27, 2004
  • Subject: Multiple Relief Line Discharge Sizing
  • Code / Section: 2003 UPC Section 608.5

Decision. A maximum of four water heater relief lines may be connected to one common drain. The drain shall be increased one pipe size for each additional connection to the water heater relief drain in accordance with the chart below. Where more than one water heater is connected to a common relief line, the drain shall not terminate within a tenant space.

Number of drains* Size of drain required (inches)
1 3/4
2 1
3 1-1/4
4 1-1/2
* This applies only to water heater relief valves with a ¾-inch outlet

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 11-002 Revised
  • Date: April 18, 2012
  • Subject: Control valve requirements for showers and combination bathtub/showers, including claw-foot bathtubs with showers
  • Code / Section: 2009 Uniform Plumbing Code (UPC) Sections 418.0 & 414.5

Decision. All individual shower control valves or combination bathtub/shower control valves that operate fixed shower heads, body sprays, or similar fixed outlets in a standup-type shower application shall conform to ASSE 1016 or ASME A112.18.1/CSA B125.1 standards. This also applies to claw-foot bathtub control valves with a fixed shower riser. This does not apply to bathtub filler valves with or without handheld shower attachments or to emergency showers.

Background. Individual shower only control valves regardless of the type of shower head, spray or handheld outlet are required to be (1) pressure balance, (2) thermostatic, or (3) combination pressure balance/thermostatic mixing valve type. All fixture fittings (valves) are required to meet ASME A112.18.1/CSA B 125.1. However, shower control valves are required to conform to ASSE 1016 or to Clause 5.10 of ASME A112.18.1 /CSA B125.1. Such valves will likely have the ASSE 1016 mark or will be identified in their listing as being an automatic compensating valve. Combination tub/shower control valves with a permanently fixed shower head, body spray or similar outlet must conform to the above requirements. This applies to claw-foot bathtubs with shower riser attachments for a standup-type shower application. Two- or three-handle control valves with a hot control on the left and a cold control on the right do not conform to ASSE 1016 or to Clause 5.10 of ASME Al 12.18.1/CSA B125.1.

The Plumbing Code and the product standards also require that shower control valves have a maximum temperature limit device that must be adjusted by the installer and is not thereafter adjustable by the user during normal use of the shower. The high-limit stop is typically an adjustable set screw or cam that is manually set to limit the travel of the control valve handle or the proportions of hot and cold water to provide a set temperature. Adjustment would typically require removal of the valve trim plate. The high-limit stop must be field adjusted at the time of installation to limit the delivered water temperature to a maximum of 120° F. This would require that the water heating appliance be in operation at the time of adjustment.

There are two types of events that the shower control valve must be designed to protect against:

  1. extreme temperature fluctuations from the user set temperature caused by changes in hot or cold water distribution line pressures, and
  2. extreme temperature conditions caused by the user either purposely or accidentally adjusting the control valve to deliver the hottest water available from the hot water distribution system. Where water inlet pressures or outlet temperatures fluctuate during shower use, control valves complying with ASSE 1016 or Clause 5.10 of ASME A112.18.1/CSA B125.1 are designed to automatically and rapidly adjust to maintain the water discharge temperature.

In a standup-type shower application where the shower head, body spray, or similar outlet is permanently fixed, a user subjected to a sudden or extreme temperature change may react by abruptly moving away from the fixed shower outlet. This abrupt movement may result in falls that could cause injury to the user. Therefore, showers and combination tub/showers must have a shower control valve that is capable of protecting an individual from extreme temperature changes or from being exposed to water temperatures in excess of l 20°F. The control valve must be installed at the point of use. In other words, the person in the shower must have access to the control handle(s) of the valve in order to adjust the hot and cold supply as desired during use. Inline-type thermostatic or pressure balancing valves do not satisfy the requirements of UPC Section 418.0.

Where a hand-held shower is connected to a bathtub filler faucet only, or where such bathtub filler faucet includes a handheld shower attachment, the faucet is not required to comply with ASSE 1016 or Clause 5.10 of ASME A112.18.1/CSA B125.11 as would be required for a standup-type fixed shower application. Additionally, the handheld shower attachment does not "reclassify" a tub filler faucet as a "combination tub/shower valve." Bathtub fill valves with or without handheld shower attachments must be limited to a maximum of 120°F by means of an inline point-of-use temperature limiting device conforming to ASSE 1070 in accordance with UPC Section 414.5.

A fixed shower riser is any method whereby the shower outlet is secured in such a way that the bather does not need to physically hold the shower outlet in order to shower while standing in the enclosure. In a standup-type fixed shower application the inspector will primarily look for the following in order to verify conformance:

  1. ASSE 1016 marking on the valve, or
  2. A single-handle control for hot and cold with an adjustment screw or cam to limit the travel of the control.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 07-003
  • Date: June 26, 2007
  • Subject: CSST Piping Termination Within a Vented Gas Fireplace
  • Code / Section: 2006 IFGC Section 403.5.4 and Manufacturer's Installation Instructions

Decision. Where corrugated stainless steel (CSST) gas piping is supplied to a factory built fireplace it shall terminate either (1) directly to the shutoff valve inside or outside of the unit which is hard-piped directly to the unit, or (2) within the unit by means of the CSST manufacturer approved termination bracket. This applies to vented gas fireplaces and vented gas fireplace heaters manufactured in accordance with Sections IFGC 604 and 605. It does not apply to decorative appliances for installation in a fireplace manufactured in accordance with Section 602.

Background. CSST is allowed to connect to non-movable appliances such as water heaters, furnaces and boilers. Vented gas fireplaces and vented gas fireplace heaters would fall within this category. As such, the termination to the appliance must be either to the hard-piped connections of the appliance (nipple, union and shutoff valve) or by means of an approved termination bracket. This is to restrict unnecessary movement of the CSST when servicing the appliance. The appliance shutoff valve must be rigidly installed such that at no time is the shutoff valve installed with CSST on one side and a flexible appliance connector on the other side.

Where CSST penetrates a metal framework of the gas fireplace it shall be protected in accordance with the CSST manufacturer’s instructions (such as using metal strip-wound material). Note that the requirement for a factory equipped grommet or sleeve in Section 411.1.3.3 applies to fireplace inserts only, which are designed for installation within a wood burning fireplace, and to the protection of the flexible appliance connector.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 05-001
  • Date: August 8, 2005
  • Subject: Dishwasher Drainage Discharge Piping and Airgap (Johnson Tee)
  • Code / Section: 2003 UPC 807.4

Decision. The PVC extension of the Johnson Tee dishwasher drainage airgap may be extended to interior or exterior locations for the purpose of providing air to prevent backsiphonage. When extended to the outdoors, they shall not extend to an upper level, nor shall they extend to an exterior wall of another unit in multi-family construction. When extended to the interior, they shall terminate within the same room as the dishwasher. Solvent cement meeting ASTM D3138 may be used for the transition from ABS to PVC in a non-pressure application. Where the termination is extended to a location away from the Johnson Tee, no portion of the extension shall be trapped and horizontal runs exceeding 12-inches shall be installed with a minimum of 1/4-inch per foot slope back to the Johnson Tee.

The pressurized discharge piping to a Johnson Tee drainage airgap fitting may be of copper or CPVC. Other materials may be used if approved for such use by the piping manufacturer and where the fittings do not reduce the internal bore of the piping. The drainage airgap fitting shall be located in the same room as the dishwasher.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 10-005
  • Date: December 9, 2010
  • Subject: Use of Double-Wye or Double-Combination Fittings in Horizontal Drain Lines
  • Code / Section: 2009 UPC Section 312.0 (See also Section 308.1)

Decision. A double-wye fitting may be used in horizontal drain lines. The use of 1/8th bend elbows at the outlets of the double-wye fitting to form a double-combination pattern is acceptable. The minimum slope of the barrel of the fitting shall be 1/4-inch per foot. Manufactured double-combination fittings are not approved for use in horizontal drain lines.

Discussion. This approval does not apply to manufactured double-combination fittings, including figure-five fittings, otherwise known as a fixture cross, or a modified double combination wye & 1/8th bend. The use of a double-wye fitting is acceptable. The use of 1/8th bend elbows at the outlets of the double-wye fitting to form a double-combination pattern is acceptable in that the elbows can be appropriately turned to allow for proper connection of the branch that is graded at 1/4-inch per foot.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • 2009 International Fuel Gas Code, Section 310.1.1
  • 2009 International Residential Code, Section G2411.1.1
  • 2009 NFPA-54 National Fuel Gas Code, Section 7.13.2

The bonding connections shall be as shown in the detail below. The point of connection to the gas piping system shall be on the metal piping (not the CSST fitting) and shall be located between the gas meter and ahead of the first joint connection of the CSST system. For propane systems, the point of connection shall be on the metal piping between the entrance into the building and ahead of the first joint connection of the CSST system.

CSST electrical bonding

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 04-003
  • Date: June 15, 2014
  • Subject: Permit Requirements for Espresso Stands
  • Code / Section: 2003 UPC Section 103.0

Decision. Espresso stands which are constructed on-site shall require a plumbing permit. This shall apply to such stands where an approved potable water source other than from the water purveyor (such as bottled water systems) is provided and/or the drain system is not directly connected to the side sewer. The potable water source and the method of drainage disposal shall be acceptable to the food program of the Environmental Health division.

Background. Espresso stands that are constructed on-site will often involve the installation of water piping or tubing, drainage materials and fixtures, and water heating equipment. Such equipment must meet minimum code requirements, such as water distribution materials approved for potable water, fixture and drainage connections, and safety devices for water heating equipment.

MEMORANDUM

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TO: Fuel Gas Piping Installers & Contractors, and Gas Piping Permit Holders

FROM: Dave Cantrell, Chief Plumbing Inspector

DATE: April 21, 2010

SUBJECT: FUEL GAS PIPING IN TOWNHOUSES


Please be aware that the International Fuel Gas Code (IFGC) as adopted by the State of Washington, the City of Seattle and unincorporated King County reads as follows:

Section 404.1 Prohibited Locations. Piping shall not be installed in or through a circulating air duct, clothes chute, chimney or gas vent, ventilating duct, dumbwaiter or elevator shaft. Piping installed downstream of the point of delivery shall not extend through any townhouse unit other than the unit served by such piping.

The underlined portion was added to the 2006 IFGC through the national code development process. The reason for this change is that townhouse construction creates some unique concerns regarding the arrangement and routing of fuel gas piping. The premise for the change is that gas piping serving a dwelling should be under the control of the occupant of that unit. Additionally, townhouses are separated by a 2-hour wall as opposed to duplexes or other types of multi-family buildings. Therefore, fuel gas piping supplying other units cannot pass through any portion of another unit, such as an attic, crawl space, floor/ceiling assembly, etc. On the next page you will find further explanation and a diagram showing one possible solution that would be code compliant.

Keep in mind that a townhouse is a single-family dwelling unit constructed in a group of three or more attached units in which each unit extends from foundation to roof and with open space on at least two sides.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 04-015 Revised
  • Date: January 6, 2009
  • Subject: Hydronic piping in concrete slabs
  • Code / Section: 2003 UPC Section 313.12

Decision. Cross-linked polyethylene piping and tubing systems (PEX) may be installed within a concrete slab for the purpose of hydronic heating (radiant floor heat) when first approved by the manufacturer.

Background. Typical installations of hydronic systems in a concrete slab floor will require that the piping or tubing be placed within the concrete on top of the wire mesh which rests on the vapor barrier above the compacted soil. This is consistent with the 2003 International Mechanical Code, Chapter 12 and the2003 International Residential Code, Chapter 21. (Note specifically Section M2104.2, Item #1 of the IRC.) While the UPC does restrict the embedding of plumbing piping in concrete, it does not specifically restrict the embedding of tubing. PEX piping and tubing is resistant to certain solvents that may affect other materials. It can be produced by several different manufacturing processes, each yielding piping or tubing complying with the referenced standards, yet each with unique characteristics. Thus, manufacturer's specifications shall apply. Manufacturer's specifications shall also apply to other types of piping or tubing materials to be embedded in concrete.

Please note that the IRC Section M2103.3 requires a minimum 100 psi pressure test of the tubing system to be held for at least 30 minutes. Non-floor type hydronic systems require the 100 psi test for 15 minutes per the IRC Section M2101.10.

Seattle/King County Public Health requires a permit and inspection for potable (flowthrough-open) hydronic piping or tubing systems. The cost shall be $10.00 per zone. Non-potable (closed) systems fall under the provisions of the mechanical codes and are thus subject to the permit and inspection processes of Seattle DPD or King County DDES.

DECISIONS / INTERPRETATIONS
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  • Decision No. 04-012 Revised
  • Date: January 6, 2009
  • Subject: Horizontal vents and fittings for vent connections to trap arms below flood rim
  • Code / Section: 2003 UPC Section 905.3

Decision.For fixtures located on floors above the lowest floor level of the gravity drain, sanitary tees may be used in a horizontal configuration below the flood rim of the fixture for the vent connection to trap arm. Combination or wye fittings shall be required for these connections on the building drain floor level and on any floor level that drains to a sump. Elbows on horizontal vents below the flood rim of fixtures on all floor levels shall be of the long sweep pattern.

Horizontal vents are permitted below the flood rim of a fixture. However, such horizontal vents when located on the building drain floor level or on any floor level that drains to a sump shall rise vertically at the nearest wall adjacent to the fixture.

Background. While the Uniform Plumbing Code has required drainage pattern fittings on all vents below the flood rim, it has been standard practice in the industry for many years to use sanitary tees in the horizontal position for the vent connection to a trap arm below the flood rim. However, sewer backups are most likely to occur on the lowest level of gravity drainage. For this reason, it is reasonable to require the combination and/or wye fittings and to place appropriate limits on the length of horizontal vents below the flood rim. Additionally, in most cases the lowest floor level will allow more room necessary for the installation of combination and wye fittings, as opposed to upper floor levels within a joist space. Revision was to fix minor misspelling in title only.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 16-001
  • Date: July 11, 2016
  • Subject: Horizontal wet venting for a bathroom group and circuit venting
  • Code / Section: 2015 UPC Section 908.2 and 911.0

Decision. The provisions for horizontal wet venting for bathroom groups have been modified from the 2012 UPC, and the circuit venting provisions have been moved from an appendix chapter to Chapter 9 also. The attached infonnation and diagrams may be helpful in understanding these relatively new and recently modified provisions. Please note that some circuit venting designs may require a plan review prior to installation (see comment to Section 911.0).

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 10-001
  • Date: January 25, 2010
  • Subject: Indirect waste receptor location for condensate drains
  • Code / Section: 2006 UPC Section 804.0 and 807.0

Decision. Hub drains, standpipes or similar drains serving as indirect waste receptors for HVAC appliance condensate drainage need not be readily accessible, but may be recessed in a wall and shall be accessible, provided that;

  1. The recessed area containing the waste receptor is sealed water-tight such that overflow of the drain will not leak into the wall cavity,
  2. The indirect connection shall be located in the area controlled by the same person controlling the conditioned space, and
  3. If a door or panel is installed to enclose the recessed area, the cover shall allow ventilation of the space and drainage of any overflow.

Background. With the anticipated increase in energy conservative appliances being installed due to updated energy efficiency regulations, condensate discharges to the exterior are resulting in freezing of the drains, which can cause damage to appliances and buildings. Condensate discharge is not as likely to splash as may be the case with fixture discharges. HVAC appliances and equipment may be located in attics and floor-ceiling assemblies over general occupancy areas, such that condensate drains are not always conveniently located near floor drains and floor sinks. It is not uncommon for designers and building owners to want to limit piping in exposed areas where it might be subject to damage or vandalism, such is in a school or similar public occupancy. Not all waste receptors are installed in readily accessible locations, such as when located beneath movable restaurant equipment so as to avoid a tripping hazard, or when a clothes washer drain connection is located behind a stackable washer/dryer combination appliance. Therefore, allowing for an accessible location in a wall that is accessible, properly ventilated, and sealed to prevent moisture intrusion is deemed to meet the intent of the code requirement.

Keep in mind also that Section 807.0 allows such connections to be by means of a fixture tail piece or a bathtub overflow. This option may be used for the discharge of a condensate pump also. Additionally, where the trap may be subject to loosing its seal, an approve trap priming device is required.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

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  • Decision No. 07-001 Revised
  • Date: June 5, 2007
  • Subject: Macerating toilet systems
  • Code / Section: 2006 UPC Section 710.13

Decision. There are some manufacturers of macerating toilet systems that only provide 1-1/2 inch inlets to the sump compartment for other fixtures. Although the minimum horizontal drain for a bathtub or laundry tray is 2-inch, we will allow a 1-1/2 inch drain connection of a bathtub, combination bathtub and shower, or laundry tray. This allowance will be for the connection of a single fixture only. Other fixtures or combination of fixtures requiring a minimum 2-inch drain shall not discharge into a 1-1/2 inch outlet of a macerating toilet system.

Background. None.

MEMORANDUM

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TO: Contractors and Installers

FROM: Dave Cantrell, Chief Plumbing Inspector

DATE: July 1, 201

SUBJECT: PERMIT AND PLAN REVIEW REQUIREMENTS FOR MEDICAL GAS SYSTEMS


Medical Gas Permits are not available to be applied for or purchased online. These types of installations require the submittal of plans and diagrams to be reviewed prior to permit issuance. Application can be made and plans submitted at the Seattle Office or the Bellevue Office.

Level 11 and Level 22 medical gas systems shall require detailed plans to include all information identified in the 2009 Uniform Plumbing Code (UPC), Section 1312.0. Please allow at least 5 working days for the plan review to be completed. Upon approval of the plan review you will be notified that your permit is ready to be issued, at which time you can purchase the permit at the permit counter. At that time you will receive a Medical Gas Installer Test Form to be filled out by the installer. A completed and signed copy of the installer test form along with the verifier’s report shall be provided to the Public Health – Seattle & King County inspector at the time of final inspection. Level 33 medical gas systems do not require a plan review, so the permit can be issued over the counter at one of our offices. However, the Medical Gas Installer Test Form is still required to be filled out as described above for Level 1 and Level 2 systems.

Medical gas systems in health care facilities are required to meet the provisions of Chapter 13 of the 2009 UPC and the 2005 NFPA 99C. Health care facilities are defined as buildings or portions in which medical, dental, psychiatric, nursing, obstetrical, or surgical care is provided. These systems would require a medical gas permit and inspections. Laboratories that are independent of a health care facility would not require medical gas permits or inspections. However, some types of compressed gases may fall under the provisions of the Fire Code or Fuel Gas Code, thus requiring a gas piping permit. Additionally, Section 3006.1 of the state adopted 2009 International Fire Code mandates that compressed gases for veterinary uses comply with the Plumbing Code. Therefore, a veterinary clinic would come under the scope of medical gas as a Level 3 system.


1 Level 1 – Systems serving occupancies where interruption of the piped medical gas and vacuum system would place patients in imminent danger of morbidity or mortality.

2 Level 2 – Systems serving occupancies where interruption of the piped medical gas and vacuum system would place patients at manageable risk of morbidity or mortality.

3 Level 3 – Systems serving occupancies where interruption of the piped medical gas and vacuum system would terminate procedures but would not place patients at risk of morbidity or mortality.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

Also available in PDF format

  • Decision No. 05-002 Revised
  • Date: June 29, 2011
  • Subject: Multiple Shower Head/Body Spray Shower Drain Sizing
  • Code / Section: 2009 UPC Table 7-3

Decision. Multiple showerheads and/or body sprays may necessitate increasing the trap and drain size to accommodate the gallons per minute (gpm) flow. The following table provides recommended trap sizing and fixture unit equivalents for the purpose of sizing the drainage system.

Total flow rate through
showerheads and
body sprays
Minimum Trap Size
(inches)
Drainage Fixture
Units
Up to 5.7 gpm 2 2
Greater than 5.7 gpm to 12.3 gpm 2 3
Greater than 12.3 gpm to 25.8 gpm 3 6
Greater than 25.8 gpm to 55.6 gpm 4 8

Background. This sizing information is based in part on Table 709.1 of the 2009 International Plumbing Code.
Note: See Decision No. 11-001 regarding replacement showers for existing bathtubs.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

Also available in PDF format

  • Decision No. 07-002
  • Date: May 15, 2007
  • Subject: Piping Support and Mid-Story Guides
  • Code / Section: 2003 UPC Table 3-2, Chapter 3 and Appendix I

Decision. For plastic DWV piping up to and including 4-inch diameter where the vertical drainage stack does not exceed 12-feet in height, the base of the stack shall be considered as being supported where such support is provided on the horizontal piping downstream of the stack within 12-inches of the fitting. Other types of DWV piping materials shall be supported in accordance with the manufacturer's instructions or the applicable product standard.

Mid-story guides for plastic DWV piping shall not be required for vertical drains and vents that do not exceed 12-feet in height and are not otherwise secured by means of connecting branches. All other piping materials shall be supported in accordance with the manufacturer's instructions or the applicable product standard.

Background. There appears to be some inconsistency in the application of support at the base of stacks and mid-story guides. The manufacturer's instructions for plastic DWV systems usually only "recommend" certain types of support, and often this seems to conflict with code interpretation. There is not significant movement in vertical plastic DWV piping as one will find with plastic water distribution systems. In addition, a 12-foot section of PVC Cellular Core DWV weighs about 12 pounds and a 12-foot section of ABS Cellular Core DWV weighs about 9 pounds. Other types of materials such as cast iron, copper and stainless steel are going to be significantly heavier.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

Also available in PDF format

  • Decision No. 04-002
  • Date: June 15, 2004
  • Subject: Plastic Water Service Termination Within a Building
  • Code / Section: 2003 UPC Section 604.14 - State Amendment (see also state amendments to sections 604.1, IS 7-90 section 601.4 and IS 8-95 section 601.4)

Decision. Plastic water service material shall terminate within 2-feet of entry into a building, at which point the connection to the water distribution system shall be made. EXCEPTION: Plastic water service material that is installed under a concrete slab is not limited to a termination point within 2-feet of entry into a building. However, the point of termination shall be made within 2-feet above the slab floor penetration. PE and PVC water service fittings shall not be allowed beneath a slab floor within a building unless acceptable to the pipe and fitting manufacturer. CPVC, PEX, PEX-AL-PEX and PE-AL-PE materials shall be installed in accordance with the UPC and the manufacturer’s specifications.

Background. The State of Washington has amended the UPC to allow for the termination of plastic water service material within a building. The requirement that the “connection to the potable water distribution system be as near as is practical to the point of entry” is not defined in the code. The purpose of this decision is to provide for consistent application of this amended provision.

Download this policy in PDF format

Purpose. The purpose of this policy is to facilitate conservation of valuable water resources by accommodating the use of harvested rainwater to supply certain types of plumbing fixtures in structures while maintaining the standards for adequate public health protection against the hazards posed by the improper use or application of reclaimed rainwater.

The purpose of this policy is to facilitate conservation of valuable water resources by accommodating the use of harvested rainwater to supply certain types of plumbing fixtures in structures while maintaining the standards for adequate public health protection against the hazards posed by the improper use or application of reclaimed rainwater.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

Also available in PDF format

  • Decision No. 11-001 Revised
  • Date: December 28, 2011
  • Subject: Replacement Shower Dimensions
  • Code / Section: 2009 Uniform Plumbing Code (UPC) Section 411.7, Exception #2 and Table 7-3

Decision. Where a shower enclosure meeting the minimum outside dimensions of Section 411.7, Exception #2 is installed to replace an existing bathtub and where the maximum gallons per minute (gpm) flow rate of all combined shower heads or outlets does not exceed 5.7 gpm, the shower drain may be served by a minimum 11h-inch trap and trap arm.

Background. This provision is a viable option for the aging or infirm population, thus allowing them to remain in their dwellings. The intent is to allow a replacement shower with overall exterior dimension of 60-inches wide and 30-inches deep. While the interior dimension of the shower is not specified, the intent is that the interior dimension would be equivalent to that of a combination bathtub/shower unit. Therefore, this replacement option applies only to shower enclosures designed to replace an existing bathtub. Since these replacement showers often will locate the drain at one end of the shower unit in order to match closely with the existing bathtub drain, the replacement shower may connect to the existing bathtub drain with minor revisions to the drain, such as installing a new trap or slightly modifying the trap arm.

DECISIONS / INTERPRETATIONS
of the Chief Plumbing Inspector

Also available in PDF format

  • Decision No. 04-011
  • Date: July 6, 2004
  • Subject: Underground Piping
  • Code / Section: 314.3 and 315.4

Decision. All piping installed under ground shall adhere to the requirements of 314.3 and 315.4. A rock larger than > 3/4" would be considered a stone. Dirt used for backfill and bedding should be strained to filter any stones. Crushed rock 3/4"< and pea gravel would be acceptable.

Background. An inspection does not routinely include verifying backfill material and method. The inspection report should indicate that the backfill is subject to code. In spot checks or on follow up inspections, if the requirements have been ignored, the inspector has thes authorization to call for a correction.

MEMORANDUM

Also available in PDF format

TO: Contractors and Installers

FROM: Dave Cantrell, Chief Plumbing Inspector

DATE: May 22, 2014

SUBJECT: PERMIT AND PLAN REVIEW REQUIREMENTS FOR WATER REUSE SYSTEMS


Water Reuse Permits are not available to be applied for or purchased on-line. These types of installations require the submittal of plans and diagrams to be reviewed prior to permit issuance. Application can be made and plans submitted at the Seattle or Bellevue permit counters.

Water reuse systems shall require detailed plans to include all aspects of the water reuse system, including but not limited to, tanks, valves, piping, components, labeling, etc. Additionally, the scope of construction (i.e., new, remodel, retrofit) shall be indicated on the application. Please allow at least 10 working days for the plan review to be completed. Upon approval of the plan review you will be notified that your permit is ready to be issued.

At the time of application submittal along with the plans, a fee of $201 must be paid. Once the plans have been approved, the plumbing permit for installation can be purchased.

Please be aware of the following:

  • Rainwater harvesting systems shall be designed by a registered design professional or a Washington State certified journeyman plumber, and the system may be installed by a Washington State certified journeyman plumber, except that a property owner may design and install a rainwater harvesting system for a single family residence except where the system will be treated for potable use.

  • Other nonpotable reused water systems shall be designed by a registered design professional or a Washington State certified journeyman plumber, and may only be installed by a Washington State certified journeyman plumber.

Download the chart in PDF format

All of the fixtures in this chart shall be supplied with hot water at a minimum of 100°F. A bidet shall be limited to a maximum of 110°F, while the other fixtures shall be limited to a maximum of 120°F. The hot water shall be in operation at the time of final inspection and both minimum and maximum temperature may be checked by the inspector.

  ASSE 10161 Shower Control Valve ASME A112.18.12 Automatic
Compensating Shower Control Valve
ASSE 10703 In-line Mixing Valve Faucet with Integral ASSE 1070 CSA B125.34 In-Line Mixing Valve ASSE 1069 Mixing Valve
Fixed shower riser5 X X        
Bathtub fill only X X X X X  
Bathtub with fixed shower riser X X        
Bathtub with handheld shower6 X X X X X  
Public lavatory     X X X  
Bidet     X X X  
Gang shower without individual control valves           X

Footnotes

1 A two-handle control valve with hot on the left and cold on the right does not meet this standard. Typically, the ASSE 1016 standard will be stamped or otherwise marked on the valve itself.

2 A two-handle control valve with hot on the left and cold on the right does not meet this standard. If the valve is not marked with the ASSE 1016 standard, the manufacturer's literature should indicate that the control valve conforms to ASME A112.18.1 and is of the "automatic compensating" type.

3 This can be installed at the source, at the point of use, or anywhere in between. A dual listed device installed at the source which conforms to both ASSE 1017 and ASSE 1070 is acceptable and shall be installed per the manufacturer's installation instructions.

4 This can be installed at the source, at the point of use, or anywhere in between. A dual listed device installed at the source which conforms to both ASSE 1017 and CSA B125.3 is acceptable and shall be installed per the manufacturer's installation instructions.

6 A fixed shower riser is a shower outlet that is designed to be used in a typical stand-up type shower application. This may also include a handheld shower that is fixed to a hook, bar, or similar support such that the shower wand is not within reach of a bather while sitting in the bathtub. Thus, it is designed to be used in a standup type shower application without the need to hold the shower wand during use.

6 The handheld shower does not meet the description of a fixed shower riser as described in Footnote #5.