Answers and Analysis

Yes. It is impossible to determine if the potable water has been contaminated with lead when 50-50 solder is applied in conjunction with lead-free solder.

Yes. The IAPMO Installation Standard 3, Section 316.1.2 (2003), Section 2.3.1 (2006/2009/2012) refers to solder joints. Section 316.1.2.9 (2003), 2.3.10 (2006/2009/2012) states, “After the joint has been completed; when cool, clean off any remaining flux with a wet rag.”

A compression repair coupling must be constructed to applicable standards, tested and listed, and then installed per the listing limitations and applicable code requirements.

Section 601.1 requires that each plumbing fixture shall be provided with an adequate supply of potable running water. The exception states “except listed fixtures that do not require water for their operation”. A nonwater urinal is a fixture that does not need water for its operation but is not specifically mentioned in the 2006 UPC. The 2009/2012 UPC contains “non water urinal” provisions in Section 402.3.1 (2009) 403.3.1 (2012).

The identification that is required by Section 301.1.2 (2003/2006/2009) 301.1.1 (2012) is applied by the manufacturer. The identification that is required by Section 601.2 is applied by the installer.

The left side of a faucet is determined when the operator is positioned inside of the fixture (tub, shower, etc.) facing the control valves.

Any valve with an opening in a pit or box below grade is a violation of Section 602.1. Since a backflow prevention device must be located above grade, the practical solution to this problem is to also install the
drain-down valve above grade.

No. Section 603.3.3 (2003/2006/2009) 603.4.2 (2012) requires that backflow prevention assemblies be tested or inspected annually. Only those devices which are testable meet the criteria necessary for compliance with this code section. Testable devices includes pressure vacuum breakers, double check valve assemblies, and reduced pressure principle backflow assemblies. Section 603.2 (2003/2006/2009/2012) identifies only these devices as backflow prevention assemblies.

No. The intent of this section is to provide permanent access to all backflow prevention devices. There is a tendency to locate these devices in locations that are inaccessible to avoid the relocation of any equipment
or the installation of any additional piping. The reference to a ladder in Table 6-1 6-2 (2003/2006/2009)
Table 603.2 (2012) notes that there may be a need to install a permanent ladder to access the platform.

Section 603.3.5 (2003/2006/2009) 603.4.4 (2012) prohibits direct connection of the potable water supply to sewer connected waste piping under any circumstances. The section later differentiates between a direct connection to drainage piping and the necessary introduction of a supply of flushing water to an open plumbing fixture or trap by means of a submerged inlet when protected by a properly placed vacuum breaker. A directly flushed siphon jet water closet is a common example. Here, a vacuum breaker protected flushometer valve delivers water to both the bowl flushing rim and the siphon jet in the bottom of the trap.
IAPMO listed open hopper commercial food waste disposers require a continuous water supply while
operating. The water usually enters the hopper through one or more strategically placed low inlets which,
are properly located on the inlet side of the appliance trap when these inlets are protected by an approved
vacuum breaker installed at a suitable height above the flood level rim of the hopper or scrap table, the
garbage disposer meets the cross-connection control and water supply safety requirements of the UPC.

No. Section 603.3.5 (2003/2006/2009) 603.4.4 (2012) prohibits connection of potable water piping to a “sewer connected waste” with or without backflow protection. A physical connection, when separated by a backflow prevention device, provides a “bridge” between the water source and the bacteria contained in the sewer piping. The only assured means of isolating the potable water system from bacterial contamination is by means of a physical airgap.

1. Yes. Devices of this type which depend on water flow in the vertical tailpiece to aspirate the sanitizing material into the water stream (no pumps or other method of pressure injection present), when properly
installed, should not constitute a cross-connection. Proper installation includes a vacuum breaker
on the pipe downstream of the flushometer valve, but ahead of the sanitizer connection.
2. Yes. The vacuum breaker for a flushometer is tested to comply with American National Standards
Institute ASSE 1001 (atmospheric type vacuum breakers) and approval under this standard requires
that the entire valve or its established critical level be installed at least 6 inches above a fixture or
source of contamination with no possibility of the device being subjected to any back pressure.
Although Section 603.4.1 (2003/2006/2009), 603.5.1 (2012) requires that the critical level of a flushometer valve vacuum breaker on a water closet or urinal be at least 6 inches above the fixture, when a device such as a sanitizing unit is added, the 6 inch minimum from the critical level to the point of the sanitizer discharger must be maintained.

The design and construction of the flushing rim jets and the flood level rim of a urinal constitute the possibility of the rim jets being flooded. This creates a submerged outlet condition. Other types of urinals
discharge the potable water through the china spreader bar or channel to the washdown jet outlets. This
china casting area is a potential for contamination and back-siphonage. For consistency and to protect the
potable water system, the 6 inch critical level requirement applies to all water-supplied urinals.

Heat exchangers represent a potential source of direct cross-connection. The only way to assure that failure of materials within the exchanger will not create such a cross-connection is to provide double-wall
separation with a path to atmosphere which will identify a failure in either of the two heat transfer walls.
Backflow protection serves no purpose when forward flow of potable water is being contaminated as it
passes through the heat exchanger. Appendix L is applicable only when there is certainty that a transfer
medium such as steam shall never be allowed to become non-potable because the steam's primary uses
(e.g., implement sterilization, vegetable steaming, etc.) require noncontaminated steam.

Yes, in accordance with Section 506.4.2(2)and(3)of the 2006/ 2009, 505.4.1 (2012) Uniform Plumbing Code and Sections 405.1,405.1.1(2) and (3) of the 2009 Uniform Solar Energy Code, a single wall heat exchanger may be used provided the heat transfer medium is potable water or has a toxicity rating is classified as 1.
Please note that both codes reference Section 603.4.4.1 (2006/2009) 603.5.4 (2012) of the 2009 Uniform Plumbing Code for protection of the potable system for single and double wall heat exchangers.

Water supply piping to such facilities should conform to the requirements of Section 603.4.5 (2003/2006/2009), 603.5.5 (2012) which requires an airgap or an appropriate listed backflow preventer.

Section 603.4.6.1 (2003/2006/2009) 603.5.6 (2012) states that lawn sprinkler systems are required to have approved vacuum breakers or other listed backflow preventers.
This Section does not permit double check valve assemblies to be used to provide backflow protection for a lawn sprinkler system.
Double check valve assemblies are designed to be used for non-toxic pollutants. Fertilizers and other
chemicals used on lawns are not non-toxic. Based upon these facts, a double check valve assembly would
not provide equivalent protection.

Yes. Section 603.4.7 (2003/2006/2009) 603.5.7 (2012) requires the installation of a listed non-removable type backflow prevention device on all hose bibbs including single-family dwellings. The exception would be a hose bibb that would be used to serve a clothes washer which has an internal airgap or a drain on the water heater.

No. Backflow preventers are not required on washing machine hose bibbs or hose bibbs used as water heater drains. Washing machines are provided with airgap fills at the factory. Therefore, the hose bibb
backflow preventer would be redundant.
Although it is conceivable that a homeowner would not have a washing machine installed and would
use the hose bibb for some other purpose, such as getting hot water to wash his car, it would be an unlikely
use for this valve.

If there is a chance of back-pressure, and the protection required is against contamination, a reduced pressure principle device would be the correct device to install. A pressure type vacuum breaker could be used if there is no possibility of back-pressure. Double check valve assemblies are designed to be used for pollution protection against food or drink materials that cause a change in color, odor, or taste, but otherwise
are not harmful or hazardous.

Boilers which are utilized exclusively for heating potable water that is intended to be used solely for domestic (potable water) applications will not require backflow protection. It is assumed that the boiler is
constructed of materials suitable for potable water distribution.

No. However, Section 603.4.12 (2003) 603.4.11 (2006/2009) 603.5.11 (2012) specifies that in cases where it is impractical to correct individual cross-connections on the domestic water line, the line supplying such outlets is considered a non-potable water line. No drinking or domestic water outlets are permitted to connect to the nonpotable water line.
Whenever possible, all portions of the nonpotable water line must be exposed and all exposed portions
must be properly identified in a manner satisfactory to the Authority Having Jurisdiction. Each outlet on the
nonpotable water line which may be used for drinking or domestic purposes must be posted: “CAUTION:
NONPOTABLE WATER, DO NOT DRINK.”

No. The UPC does not regulate the material and installation of non-potable water piping within or under a building. Refer to the definition for plumbing system that is found in Section 218.0. The piping, however,
must comply with the building code regarding fire prevention requirements, including penetrations of floors,
walls, etc.
The code provides requirements to protect the potable water system and guidelines to identify nonpotable
water piping, including exposing the piping whenever possible.
The Uniform Swimming Pool, Spa and Hot Tub Code (2006/2009/2012), permits the installation of listed
plastic circulating piping of not less than Schedule 40. The piping must also comply with the building code
regarding fire prevention requirements.

Section 603.1 (2003/2006/2009) 603.2 (2012) requires that all backflow prevention devices be approved for their intended use prior to installation.
When an appropriate device is unavailable, it then becomes necessary to exercise administrative
Judgment (under the provisions of Section 301.0, 2003/2006/2009/2012) to reach the best compromise option.

Copper piping should never be intentionally exposed to carbonated water. The objective of installing an approved backflow prevention device between potable water piping and a CO2 injector is to prevent this
mixture from occurring inadvertently.
Copper sulfate (carbon dioxide + copper piping) is toxic and may result in illness or death, thereby
necessitating the requirements of Section 603.4.13 (2003) 603.4.12 (2006/2009) 603.5.12 (2012).

Potable water must always be protected from backflow, which could degrade its potability. If the process of treating the potable water represents a threat to its potability, then all such "treated" water must be isolated
by appropriate backflow protection. If neither the treatment nor the application of the water results in degradation of its potability, then no special backflow protection is necessary.

No. Section 603.4.15 (2003) 603.4.14 (2006/2009) 603.5.13 (2012) specifically prohibits the location of backflow preventers in any area “containing fumes that are toxic, poisonous or corrosive.” A backflow preventer that opens to atmosphere is especially unacceptable because there is a possibility of drawing contaminated vapors into the water piping system through the air intake.

Yes. Section 603.4.16 (2003) 603.4.15 (2006/2009), 603.5.14 (2012) states that Deck-mounted or equipment-mounted vacuum breakers shall be installed in accordance with their listing and the manufacturer’s instructions, with the critical level not less than one (1) inch (25.4 mm) above the flood-level rim

1. Section 604.1 points out that dissimilar water piping materials may not be intermingled, except where deemed as an acceptable practice by the Authority Having Jurisdiction.
Section 604.1 further recognizes that buried steel water piping may be subject to external corrosion
not encountered by parts of the system inside a building. This accounts for the “where otherwise
approved” provision which permits the Authority Having Jurisdiction to allow interconnection of necessary
dissimilar materials that conform with Section 311.6 (2003/2006/2009) 310.6 (2012) and covers replacement of a corroded steel water service with copper. Section 311.6 (2003/2006/2009) 310.6 (2012) provides that, where permitted, critical points of intersection of dissimilar metals must be readily accessible for observation and possible repair.
2. When installing a steel water softener, water heater, or similar equipment in a building plumbed with
galvanized steel water piping, short sections of non-ferrous piping, or tubing, such as, the commonly
used copper connector, appears to have only a minimal detrimental effect. However, the intermembering
of additional amounts of dissimilar metals should be avoided..

No. With the possible exception of points of connection to steel water heaters or similar tanks, the use of intervening steel pipe nipples at any point in a copper water piping system is an unacceptable practice.
The use of brass valves, fittings, or nipples to isolate small amounts of galvanized steel pipe from
predominately copper water systems does not, in the opinion of the committee, waive the provisions of
Section 311.6 (2003/2006/2009) 310.6 (2012) which would require that the point of connection of dissimilar metals be confined to exposed accessible locations.
Since it is doubtful that the position of the riser above the shower valve could satisfy the access provisions
of this Section 311.6, galvanized steel risers should not be used in otherwise copper systems.
Intermembering of dissimilar metals, which are widely separated on the galvanic scale, creates a
potential for electron flow, especially when an electrolyte (water) bridges the point of connection between
these metals. Steel (anode) is sacrificial to copper (cathode) and will degenerate to the point of failure over
a period of time. The length of time is dependent upon two factors:
1. The total mass of copper relative to the total mass of the steel.
2. The purity of the copper (brass, bronze, and other alloys are less aggressive than pure copper, but they
will eventually cause degeneration of ferrous metals when directly connected, especially steel piping
containing an electrolyte).
The installation of brass valves, fittings, or nipples serves to retard the rate of galvanic corrosion, but
does not provide dielectric isolation.

Yes, it is permissible to use CPVC in the ground inside or outside the building. It may also be used above grade inside the building, provided that it is properly supported. CPVC should not be subjected to sunlight
and is not permitted to be installed above ground outside of or on the surface of the building.
See also IS 20

When PVC is used for cold water piping outside of a building, the PVC piping may extend for a maximum of 24 inches above grade per Installation Standard IS 8. This is permitted, provided that the piping is properly
supported and protected from damage.
There are no restrictions as to what type of plumbing outlet or fixture may be served. Section 313.4 of
IS 8, states “where exposed to sunlight the pipe shall be wrapped with at least 0.040 inch of tape.” Painting
the pipe would not be acceptable in lieu of wrapping the pipe with tape.

Yes. The use of PVC in an all copper system does not present a problem because of the very nature of plastic material. Plastic material is not a conductor of electricity; therefore, it is compatible with all metals.
Section 311.6 (2003/2006/2009) 310.6 (2012) relates to the mixing of dissimilar metals but when they are mixed, they must be readily accessible for observation and possible repair. The use of PVC as a water service in an otherwise all copper system will not effect the PVC or the copper.
When a metal water service is replaced with PVC, the ground may be disconnected from the electric
service; therefore, a new grounding system will have to be provided.
Additionally, IS 8 requires a label in the main electrical panel stating “This structure has a non-metallic
water service.”

IAPMO Installation Standard IS 20 very specifically defines CPVC as suitable for "hot and cold, water within buildings." Section 604.1 allows the use of CPVC for "cold water distribution systems outside a
building."
Nonetheless, each local Authority Having Jurisdiction has the prerogative of allowing CPVC for hot
water distribution outside of the building when all concerns have been addressed by an alternative method
of installation.

Yes, such fixture units with integral supply shutoff valves have been successfully utilized in multi-bathroom construction, particularly in apartment and hotel buildings for many years and when adequately designed
should constitute code acceptable shutoff valves.
While some designs permit flow control and shutoff without removal of a trim plate, the prime purpose
is to facilitate fixture supply valve maintenance which usually necessitates the removal of the valve handle,
trim plate, valve stem, etc.

No. The shutoff valve is required to be accessible. However, there are other configurations which could satisfy this requirement.

Apartment building water supply valving must conform to Section 605.0 (2003/2006/2009) 606.0 (2012). This means that separate water supply control valves must be provided for each living unit in the building or for each plumbing fixture or appliance in any such unit to minimize service disruption.
While hose bibbs constitute acceptable control valves for hose connected appliances such as clothes
washers, they are neither plumbing fixtures nor appliances for the purpose of Section 605.0, and consequently equipping them with control shutoffs is strictly optional.
Except in the event of accidental breakage, normal hose bibb maintenance should be accomplished
during water off-use periods.
An individual shutoff valve may be required ahead of a hose bibb to protect the hose bibb from freezing
in accordance with Section 313.6 (2003/2006/2009) 312.6 (2012).

Basic environmental sanitation principles dictate that plumbing fixtures normally using both hot and cold water are adequately supplied and that water supplies to individual family units be segregated and valved
to minimize service disruption.
The wording of Section 605.3 (2003/2006/2009) 606.3 (2012), such as, a separate fullway valve to each building, and a fullway valve shall be installed for each apartment, was intended to complement the above premise and that the phrase water supply includes both hot and cold water.
This Section 605.3 regulates the condition cited in the question and would require shutoff valves controlling
both hot and cold water supply to each building in the complex and, in addition, valves isolating each living
unit in the building or each plumbing fixture. A master control valve must be installed adjacent to the water
meter to control the site service.
This Section also 605.3 requires control valves to be accessible. Because safety is not involved and good
management procedures usually necessitate an on-site piping maintenance plan where complex installation
exists, no requirement is included governing specific valve locations or markings.

1. A "fullway" valve will have an interior flow passage with an area equivalent to that of the pipe to which it is connected. 2. The "control valve" referenced in Section 605.5 (2003/2006/2006) 606.5 (2012) could be a valve complying with the requirements of Section 605.4 (2003/2006/2006) 606.4 (2012) to which one or more supply tubes may be attached, provided the valve in question is designed to a standard which supplies the demand load requirements of each branch outlet.
3. "Saddle" valves and other branch connections which are "saddled" onto a water supply pipe would be
acceptable only if listed for that application. Sections 301.1.1 and 301.1.3 (2003/2006/2009) 301.1 and 301.1.2 (2012) require that all devices used or entering into the construction of plumbing systems shall conform to "approved applicable standards." The value listing is evidence of this compliance and will also stipulate how the product is to be installed, and will note any limitations regarding its use.

No. The compression fittings utilized in the inlet side of the angle stops are adjustable rigid joints and “shall not be considered as slip joints (see Section 705.3.3 (2003/2006/2009) 705.10.3 (2012)).
See also 221.0, Slip joint

No. This Section states that a control valve shall be installed immediately ahead of each water-supplied appliance and immediately ahead of each slip joint or appliance supply. Any fixture supplied with pipe
having no slip joints would not require a shutoff valve.

Clothes washer water supply hose connection control valves are both service and emergency shutoffs and should be accessible although not necessarily visible from every angle.
Recognizing a preference for uncluttered walls and that many such hoses remain under constant pressure,
practically operable control valves located below the top of the appliance or in from an open side to
be easily reachable without moving the appliance should satisfy the “accessible” requirement of Section
605.6 (2003/2006/2009) 606.6 (2012).

The 2012 UPC allows the use of stainless steel pipe and Section 605.17.3 Stainless Steel to Other Materials states: Where connecting stainless steel pipe, mechanical joint of the compression type, dielectric fittings, or dielectric union in accordance with ASSE 1079 and designed for the specific transition intended shall be used.

1. The joints on the compression fitting as described are slip joints (see Sections 221.0, Slip Joint, and 705.3.1 (2003/2006/2009) 705.10.1 (2012).
2. In water piping, slip joints may be used only on the exposed fixture supply line (see Section 606.2.3 (2003/2006/2009) 605.15 (2012).

Although pressure regulators are not specifically mentioned, Section 610.2 requires that the pressure loss through such devices must be included in the pressure loss calculations of the system. Similarly, the second paragraph states that “No water filter, water softener, backflow prevention device or similar device regulated by this Code shall be installed in any potable water supply piping when the diameter of the inlet or outlet of any such device or its connection piping is less than the diameter of such water supply piping, or when the installation of such device produces an excessive pressure drop in any such water supply piping.”
Based on these requirements, the opinion of the committee is that the pressure regulator must be the same size as the piping served, unless justified by water system sizing calculations done in accordance with Appendix A (2003/2006/2009/2012).

The pressure regulator should be installed at the house, leaving added pressure in the water service to operate lawn sprinklers, hose bibbs, etc. One of the conditions for approving pipe is that the pipe must be
able to withstand the working pressure provided by the water supplier.

Water pressure regulators are usually installed in the building supply of the building to regulate the water pressure to the building, leaving the higher pressure to the outside yard piping. Section 608.2 requires a pressure regulator to be installed when the main pressure exceeds 80 psi.
However, any devices or elevation changes which influence the static pressure may be considered
when determining the need for a pressure regulator. If the static pressure in the street main varies, then
the basis for the installation of the pressure regulator is determined from the high pressure, but the piping
design is based on the low pressure.

1. Yes. The intent of the readily accessible requirement for the strainer is to provide a totally unobstructed or unimpaired clearance to access the regulator assembly for servicing.
2. Yes. The same answer for question #1 applies to question #2.

Yes, Section 608.3 of the UPC states that systems that contain check valves, backflow preventers or other devices that prevent dissipation of pressure due to thermal expansion shall be provided with “an
approved, listed, and adequately sized expansion tank or other approved device having a similar function
to control thermal expansion”.
At this time IAPMO has listed this type of valves for a number of manufacturers. Valves that discharge
at preset pressures ranging from 80 to 125 psi can be provide by most manufacturers.

Yes, section 608.3 states that “any water system” that has been closed with any device that prevents water within the system from expanding back into the water main be provided with an approved expansion tank
or other approved device to control thermal expansion.

Section 608.3 requires a pressure relief valve for a “closed” water piping systems. While the average domestic water softener installation normally does not create a closed system, the Water Conditioning
Foundation Industry standards covering water softeners does not preclude the manufacture and certification
of units embodying components that can act as check valves. The Water Conditioning Foundation
standard requires that system pressure relief valves be installed in conjunction with such softeners, but
currently no warning marking is required on the appliance.
These installations present a small inspection problem that is addressed by Section 608.3, which
makes a system combination temperature pressure relief valve mandatory when a storage-type water
heater is installed.

No, although a foot valve is a device that could prevent pressure relief through the building supply, private water well systems are normally designed to pump water through a storage tank which stabilizes the pressure
and operates the same as an expansion tank.
An expansion tank, as required by Section 608.3, is not necessary in a private well water system which
has a storage pressure tank between the foot valve and the building piping system.

Section 608.3 specifies “Any water system provided with a check valve, backflow preventer or other normally closed device, shall be provided with an approved, listed, adequately sized pressure relief valve”.
In these terms, the combination temperature pressure relief valve shall have a thermal expansion relief
capacity equal to or greater than the rated heat input of the water heater. The actual size would be
dependent upon both the water heater and the pressure relief valve rating.

The installation of heat trap nipples should be in compliance with the condition of their listing. Note: There is evidence that similar products have been tested, however, at this time a listed device is
unavailable.

There is no provision in Section 608.3 which allows thermal expansion to be controlled by the size of the water system

The "Watts Governor 80" is a listed device to be used for the secondary purpose to provide pressure relief and control, thermal expansion and; thus, would be in compliance with the intent of Section 608.3.
Alteration of any listed product automatically voids its listing. Therefore, removal of the relief valve
portion of a "Watts Governor 80" would make it unsuitable for any purpose.

Installations which share a common cold water source and that have no more than one backflow preventer installed need to be provided with no more than one expansion tank or relief device downstream of the
backflow preventer. Every device that is installed to accommodate thermal expansion shall be sized to
relieve the maximum potential expansion based upon the total Btu input of all connected water heating
devices. The type of building or its intended utilizations are inconsequential; the unrestricted ability of
thermal expansion to be relieved, regardless of the number or location of all connected water heaters, is
the sole objective of UPC Section 608.3.
The installation of one backflow prevention device on the cold water supply will require no more than
one thermal expansion device on an otherwise unrestricted water system.

Yes. The first paragraph of Section 608.3 of the 2006 UPC states, “Any water system provided with a check valve, backflow preventer, or any other normally closed device that prevent dissipation of building pressure back into the water main shall be provided with an approved, listed and adequately sized expansion tank or other approved device having similar function to control thermal expansion,” regardless of the source of the thermal expansion. The second paragraph of section 608.3 deals with water heaters installed in an open system, where pressure may dissipate back into the city mains.
In this type of system a tankless water heater having an inside diameter of less than 3 inches is exempt from the requirements for temperature and pressure relief.
When water is heated it expands. For example, water heated from 90°F to a thermostat setting of 140°F in a 40 gallon hot water heater will expand by almost one-half gallon. This is because when water is heated, its density decreases and its volume expands. Since water is not compressible, the extra volume created by expansion must go someplace. During no-flow periods in a system, pressure reducing valves, backflow preventers, and other one-way valves are closed, thus eliminating a path for expanded water to flow back to the system supply.
Thermal expansion of water in a closed plumbing system can create a number of annoying and potentially dangerous problems. These include: the build up of unusually high pressure in a system (even when a pressure reducing valve is installed); pressure surges; and the chronic or continuous dripping of a temperature and pressure (T&P) relief valve. In addition, dripping faucets and leaking toilet tank ball cock fill valves are also symptomatic of thermal expansion.
More serious problems can also occur due to thermal expansion. When dangerous pressures are built up in a water heater, internal parts may fail such as the internal flues, fittings or water connections. If a flue way collapses it can lead to the potential release of toxic gases, such as carbon monoxide into living spaces. Thermal expansion can also lead to a ruptured or distorted water heating tank and may void the manufacturer's warranty.

Section 608.3 of the 2009 UPC states, “Any water system provided with a check valve, backflow preventer, or any other normally closed device that prevents dissipation of building pressure back into the water main shall be provided with an approved, listed and adequately sized expansion tank or other approved device having a similar function to control thermal expansion…” As stated, this requirement would apply to all water systems with water heating devices regardless of type.

No. Section 608.5 is very specific about the materials which may be used for relief valve drains. Such materials include “galvanized steel, hard drawn copper piping and fittings, CPVC, with fittings which will not
reduce the internal bore of the pipe or tubing.” Flex connectors violate the requirement for hard drawn
copper; and they will, in most cases, also reduce the internal bore of the drain.

No. The described receptor is not acceptable for the termination of a temperature/pressure relief valve drain because of the location above the sink or fixture and the possibility of very hot water or steam
splashing and burning or scalding a person who is using the fixture or is standing close by the fixture in the
room.

Yes. Both Section 608.5 and the ANSI standards require full size relief valve drain piping, so installed as to allow complete drainage of both the valve and discharge line.
The internal diameter of such drain piping relates directly to the designed pipe size of the relief valve
and not the throughway area of its seat.

No. A garage floor does not constitute an approved location for the relief valve drain termination. The use of garage areas for purposes other than garaging a vehicle is increasing, with garages being
used as the location for home laundry equipment, and storage of seldom used household articles, home
workshop equipment, etc. We also find garages converted into “play rooms” or other non-code uses that
are beyond the control of the Authority Having Jurisdiction.
Although the garage is not designed for other uses, there have been cases where the courts have
found the jurisdiction liable for water damage where personal property or equipment has been damaged
by the discharge of relief valves onto the garage floor.

Section 608.5 states: “No part of such drain pipe shall be trapped or subject to freezing”.

The intent of the 6 inch minimum distance required from the end of the pipe to the ground or grade level is to assure that the end of the potable relief valve discharge pipe will not be submerged or come in contact
with any substance that could pollute or contaminate the potable water system.
The intent of the 24 inch maximum distance required from the end of the pipe to the ground or grade
level is to prevent a person who could be close to the pipe at the time of discharge from being burned.
Section 608.5 states that pressure relief valve drains may terminate at other approved locations.
Approved indirect waste receptors installed inside the building may be utilized with an approved airgap.

Yes. Under certain conditions which have been approved by the local Authority Having Jurisdiction, a separate drain for each temperature and pressure relief valve may not be required if the following conditions
are met.
Where two or more temperature and pressure relief valve drains are connected to a common drain,
the drain size must be not less than the aggregate cross-sectional area of the drains which are connected
together. An example would be two T&P valves, 11⁄4 inch; three T&P valves, 11⁄2 inch, etc.

Section 608.5 allows termination at "other approved locations," and the primary or preferred location may be "outside of the building." Section 804.1 (2003/2006/2009/2012) (indirect waste receptors) requires that all
receptors "be of such shape and capacity as to prevent splashing or flooding." An indirect waste receptor
which meets this criteria would be acceptable per code as a point of collection for relief valve discharges.

The use of a mop basin for an indirect waste receptor would require the approval of the AHJ.

Yes. Per Section 608.5 the approved materials for the drain on a water heater T&P are: galvanized steel, hard-drawn copper, CPVC or a listed relief valve drain. PEX tubing is not an approved material. The use
of brass insert fittings is irrelevant. Code also stipulates “tubing” approved for this application shall be
“straight lengths as opposed to coils.”

No. Section 603.3.5 (2003/2006/2009) 603.4.4 (2012) prohibits direct connections between potable water and waste systems.

Per Section 608.5, CPVC is an approved material for use as a drain tube for water heater relief valves. The product has a ¾” male NPT by glue fitting and the OD of the tubing is 7/8 inch. This fitting would be equal to the same copper fitting, and any steel nipple and fitting installation. All are equal standards in the industry, and have set the OD’s of different pipe materials to facilitate the use of fittings and pipe threads etc… that work for a number of pipes. For instance, ¾ copper tube may be used in type K, type L or Type M pipe. The OD of all three is the same while the ID is different on each. They are all called ¾ pipe and all use the same fittings to join them.

1. Yes.
2. Section 608.7 requires a vacuum relief valve when the entire hot water tank is located at an elevation above the fixture outlets.

Introducing air to the interior of a dip tube will “break” a siphon in all cases. Water heaters with anti-siphon ports in the top of their dip tubes are not subject to siphonage. Storage tanks that have an indirect heat source (a heat exchanger within the storage tank, or hot water circulated from the heat source to the storage tank) may or may not have an internal means of preventing siphonage. Those not designed or installed in a manner that specifically prevents siphonage shall be provided with a vacuum relief valve to provide the necessary anti-siphon protection.
When any configuration of piping or tank design and installation could result in potential siphoning of the contents of the tank, an appropriate vacuum relief valve must be installed as instructed by the manufacturer.
Storage tanks that have an internal anti-siphon port in their fill tubes (such as listed water heaters) would not require an additional vacuum relief valve.

The use of a “saddle tap” is limited to a product which is listed or labeled by a listing agency acceptable to the Authority Having Jurisdiction, and is installed in accordance with the condition(s) of its listing.
Note: Installation standards only apply if they are adopted and these two are for PVC yard piping and
Asbestos cement pipe only

There is no requirement to supply a union for a “water supply inlet” as such. While it is true that most water services are provided with a union at the building, this is frequently as
a convenience to the installer, not necessarily the building owner.
Section 609.5 does require a union in a water supply system within 12 inches of regulating equipment,
water heating, conditioning tanks, and similar equipment which may require service by removal or replacement.
Since these valves do not ordinarily require service by removal or replacement, this is not intended to
include the required fullway control valve that is generally located at this position.

Yes. Section 609.5 stipulates that unions shall be installed within 12 inches of water supplied equipment which is likely to require removal for repair or replacement.

Mechanical shock arrestors are required on all building water supply pipe materials in which quick-acting valves are installed per Section 609.10 (2003/2006/2009/2012) of the Uniform Plumbing Code (UPC).

Most valves that are operated with an electrical solenoid have been determined to be quick-acting. Valves that can be quickly opened and more importantly, closed, but not designed for that action, are not considered
quick-acting.
Some flushometer valves are capable of operating as quick-acting valves but many of them can close
slow enough to be considered slow acting and would not require a mechanical shock arrestor based on
the system pressure, pipe size and water velocity. Although the code does not define, “quick-acting valve”,
it is defined in the 2006 Illustrated Training Manual as “a valve or faucet that closes automatically when
manually released or electrically actuated.”
Water hammer or fluid hammer, is a pressure surge or wave resulting when a fluid in motion is forced
to stop or change direction suddenly (momentum change). Water hammer commonly occurs when a valve
is closed suddenly at an end of a pipeline system, and a pressure wave propagates in the pipe.
According to the book by Thorley, ADR, Fluid Transients in Pipelines, a Professional Engineering
Publishing, 2004, the size of the water hammer pulse can be estimated from the Joukowsky equation. The
pressure wave comes about due to Newton's laws of motion and the continuity equation applied to the
deceleration of a fluid element. The speed of sound or pressure wave in a fluid at peak pressure will
depend upon the fluids compressibility.
According to the calculations the pressure spike achievable by a quick closing valve that can close in
less than one second can be as much as 60 times the flow velocity.
For example: Given a flow velocity of 5 feet per second in a water supply pipe in a branch, and with a
valve closing in less than one second the pressure wave can reach about 300 PSI. Given a flow velocity
of 8 feet per second, the pressure spike achievable is 480 PSI. A flush valve can be a quick closing valve
depending on the system water pressure, pipe size and flow velocity.
The Authority Having Jurisdiction (AHJ) would have to make the final determination if flushometer
valves would meet the criteria in the definition.

The second sentence of Section 609.10.2 (609.10.1, 2006/2009) is independent from and unrelated to the first sentence. The intent of this requirement is to provide accessibility for repair or replacement. Section
310.4 reinforces this requirement as, "In instances where the Code, applicable standards or the manufacturer's instructions conflict, the more stringent provisions shall prevail."

Table 6-6 is designed to maintain the maximum flow velocity of eight (8) feet per second. Table 6-6 is a basic sizing table designed for the sizing of smaller systems. When used to size larger systems it has a tendency to oversize the pipe. Appendix A provides a method to size the piping system to a minimum to save on piping costs. As a result close attention must be paid to the velocities created by the flow through the pipe when calculating its size. Section A 6.1 limits the velocity to a maximum of ten (10) feet per second or the maximum allowed by the manufacturer of the material being used. For example the maximum velocity allowed in copper pipe is eight (8) feet per second.

Section 610.13, Exception 7 specifically exempts all exterior non-potable irrigation water supply piping, both pressure and non-pressure, downstream from an approved backflow preventer from size and material
requirements. This exemption prevails whether the device be atmospheric or pressure type.
It should be noted however, that the materials and sizing waiver applies only to irrigation systems and
that the potable supply system must be adequately sized for the combined load.

Water piping installed “within a building and under a concrete slab resting on the ground” shall meet the requirements of Section 609.3 of the UPC. This section addresses the installation of ferrous and copper pipe only. All other materials are required to be installed per applicable IAPMO installation standards (see Appendix I) or manufacturer’s specifications. Where there are conflicts between the code and installation instructions, the most restrictive requirements shall be met. It is always best to get the approval of AHJ before installation begins.

Yes. Section 603.4.21 (2006), 603.4.20 (2009), 603.5.19 (2012) is quite specific and requires the installation of a reduced-pressure principle backflow preventer for “dialysis water systems, semiconductor washing systems, and similar process piping systems”.

Yes, section 603.5.10 requires a double check or RPBP to be used on the makeup water supply. If any chemicals are added to the system or used to purge the system when cleaning an RPBP would be mandatory.

A double check valve assembly is a low hazard device that protects the aesthetic qualities of the potable water. (See Pollution)

An RPBP is a high hazard device that protects the potable water against poisoning or the spread of disease. (See Contamination)

Yes. All Plastic materials for water service piping outside underground shall have a blue insulated copper tracer wire or other approved conductor installed adjacent to the piping. Access shall be provided to the tracer wire or the tracer wire shall terminate above ground at each end of the nonmetallic piping. The tracer wire size shall be not less than 18 AWG and the insulation type shall be suitable for direct burial.

No, Reduced pressure backflow preventers are not designed, approved, or intended to be used as a pressure reducing device. Its intended purpose is to protect against back pressure and back siphonage only. A PRV and RPBP are not interchangeable. They have independent and specific functions. A water pressure regulator is intended and required to be installed ahead of all other devises in the water piping system to protect them from the excessive pressure. Therefore its function would not be affected by the RPBP if installed upstream. Neither is the function of the RPBP affected by the PRV if located downstream of the PRV because the reduction in pressure is rendered constant at that point.

Section 608.2 (2006/2009/2012) UPC requires the installation of a Pressure Reducing Valve (PRV) on all water systems where the pressure exceeds 80 psi. With the installation of the PRV, the code also requires the installation of a device to provide for thermal expansion. Though the code does not specifically provide a maximum pressure on the downstream side of the PRV, good plumbing practice would dictate that the pressure should be no higher than 80 psi under normal operating conditions, including during periods of thermal expansion.

Yes, in this case the type of equipment being isolated from the potable water supply dictates that the water downstream of the reduced pressure principle backflow prevention device would be classified as “non-potable”. The only concern would be the possible cross contamination of the water feeding different types of equipment and if that contamination would be detrimental to the operation of that equipment or production of a product.

1. No. A fullway valve is required to be installed on the cold water supply pipe to each water heater at or near the water heater as a minimum; an additional fullway valve on the hot outlet of a water heater is not prohibited.
2. No. The code does not prohibit the use of a valve on an expansion tank. It is not good practice to have a valve installed on an expansion tank because it could easily be closed and prevent a place for the thermal expansion of the heated water.

Section 608.5 of the UPC lists CPVC as an acceptable material for relief valve drains for water heaters as long as it is the same nominal pipe size as the outlet of the drain valve.

Section 609.2 addresses the physical separation of domestic water piping and sewer or drainage piping constructed of clay or materials not approved for use within a building. The purpose of this section is to prevent the possible contamination of the potable water system by non-potable water, either sanitary or storm.

No, there are no exceptions. Section 604.11.2 (2009), 604.13 (2012/ 2015) does not specify the type of water heater the rule applies to. Therefore, the rule would apply to all types of water heaters (electric, gas, instantaneous, etc.).

Section 603.4.17 (2009), 603.5.16 (2012), 603.5.15 (2015) is referring to two separate installations; however, the reasoning behind the height requirements is similar. Atmospheric vacuum breakers must be located at least 6 inches above any and all downstream piping. When a hose is attached to these outlets as with a bed-pan washer, maintaining that height requirement becomes more difficult, which is a major factor in the height requirement for both the bed-pan washer and for the hose connection. These applications can be considered a high risk or health hazard. So ensuring that the AVB is at a proper height and not subjected to backpressure is critical.

Yes. Section 604.13.2 (2009), 604.13 (2012/2015) specifically states that “PEX, PEX-AL-PEX, PE-AL-PE, or PE-RT tubing shall not be installed with the first 18 inches of piping connected to a water heater”. This section of the code applies to all water heaters regardless of the type or heat source.

No, “sharkbite” fittings are push fit fittings per Section 605.3.3.3 of the 2012 UPC. A definition of pipe union is “a device used to join two pipes by drawing together flanges fitted over their ends.”

Per Section 608.2 of the 2012 UPC, “pipe size determinations shall be based on 80 percent of the reduced pressure when using Table 610.4”. If the reduced pressure at the pressure reducing valve is 70 psi the downstream piping from the PRV would be sized using Table 610.4 at 56 psi with 60 feet developed length to the furthest outlet.

Water heater drain pans are designed to receive water from leaks and are not designed to handle full open discharge of a ¾’’ or larger discharge line. Pans are located in a manner that allows leaks to be detected before damage occurs to the structure. The pans are not designed or intended for the purpose of serving as receptors. The intent of the code is to deliver the discharge from the T & P valve unobstructed and directly to the drainage system or outside.
Note: A 3/4 water line can deliver 16 to 18 gpm while a 3/4 drain flowing at 2 to 3 ft per second will only flow 2 to 3 gpm.

1. No. Per Section 1503.9.3 of the 2018 Uniform Plumbing Code, there are no special requirements for marking of grey water subsoil irrigation field pipe and fittings. Sections 1504.8 and 1505.7 does refer the installer to Section 601.3 for marking information for gray water and treated reclaimed water systems.
2. Yes. Section 1501.7 requires grey or reclaimed water to “meet the applicable water quality requirements for the intended application as determined by the Authority Having Jurisdiction”. Grey water used for subsurface irrigation is not required to be treated.
3. Yes. Per Section 1501.7 only water that is treated to applicable water quality requirements may be used above grade. Grey water used for subsurface irrigation is not required to be treated.

The 2018 Uniform Plumbing Code does not have a maximum height that the device may be installed above grade or the floor. Section 603.4.3, does however require a minimum of 12” between the lowest portion of the assembly to grade, the floor or platform and if the assembly is installed 5’ above the floor/grade, a platform is required that is capable of supporting persons preforming maintenance or testing.

National Fire Protection Association (NFPA) 13D provides design and installation requirements for two basic types of residential fire suppression systems, multipurpose and standalone. Multipurpose systems integrate the fire sprinklers into the potable water piping, thereby eliminating the need for backflow protection. Standalone residential sprinklers use a separate piping system that must be isolated from the potable water system by a backflow preventer. Neither the Uniform Plumbing Code, nor NFPA 13D address the hazards of “dead legs”* when installing a multipurpose system. Good plumbing practice however, dictates that the design of the system should insure adequate circulation of the water throughout all parts of the system to prevent the growth of bacteria.

*The term dead leg is typically used to describe a run of pipe that is no longer in use or a pipe that has become isolated from the regular flow of water.

Pipe insulation shall be installed per Section 609.11.2 of the 2015 Uniform Plumbing Code. Per Section 102.8, Jurisdictions that adopt Appendix L may utilize the requirements found in Table L 603.3.3 with prior approval from the Authority Having Jurisdiction.

1. No. Pre-pressurized water expansion tanks intended for use in potable water systems shall meet the requirements of IAPMO/ANSI Z1088-2013 (see 2018 UPC Chapter 17) and Section 608.3, which states that they shall be installed per the manufacturer’s instructions and the latest edition of the Uniform Plumbing Code.
2. Many states require an ASME listed expansion tanks when one of the following is met; a) heat input meets or exceeds 200,000 BTU; b) the water temperature exceeds 210°F; 3) Nominal water containing capacity exceeds one hundred twenty gallons.

1. All piping and equipment downstream of the backflow preventer required in Section 603.5.18 of the 2018 Uniform plumbing Code (UPC) is considered process piping and would not fall under the scope of the UPC. The Association for the Advancement of Medical Instrumentation (AAMI) publishes standards for the installation of piping and equipment for hemodialysis applications.

Yes.
1. Section 605.16.1 of the 2018 Uniform Plumbing Code specifically states, “Joints from copper or copper alloy pipe or tubing to threaded pipe shall be made using a copper alloy adapter, copper alloy nipple (minimum 6 inches)dielectric fitting, or dielectric union in accordance with ASSE 1079.” Additionally, Section 606.5 requires a control valve on the water inlet to the water heater and unions, per Section 609.5, on the pipe connections.
2. ASSE 1079 is the standard for Dielectric Pipe Unions. It does not apply to other types of unions.

Note: Section 102.1 would apply only if the water heater manufacturer specifically requires dielectric protection on their product.

1. Yes. The term appliance, referenced in Section 606.5 of the 2015 Uniform Plumbing Code, is a plumbing appliance as defined in Section 218.
2. No. By definition, tub/shower valves, hose bibbs, washing machine stops, etc. would be considered fixture fittings*.
3. Per Section 606.5, parallel water distribution systems are required to have a shutoff valve for each fixture or appliance either at the manifold or at the fixture or appliance. When manifolds are located in areas that are not readily accessible, a valve is required at each individual fixture or appliance. When installing a parallel water distribution system, a valve is required on every fixture or appliance, regardless of the type of joint used to connect the fixture or appliance to the water distribution system.

*Section 208.0 Fixture Fitting – A device that controls and guides the flow of water.

1. No. The intent of Section 605.3 of the 2009 Uniform Plumbing Code, is to provide a means of shutting off the water to a single dwelling unit without disrupting the water supply to other dwelling units. This can be accomplished by installing a shutoff valve at the water distribution line(s) to each dwelling unit or by installing individual shutoff valves at each fixture and water fed appliance within the unit.
2. Yes.
3. Yes

Per Section 301.2 of the 2018 Uniform Plumbing Code (UPC), all “pipe, pipe fittings, traps, fixtures, materials, and devices used in a plumbing system shall be listed (third party certified) by a listing agency (accredited conformity assessment body) as complying with the approved applicable recognized standards referenced in this code…”. Acceptable methods to relieve thermal expansion, per Section 608.3, are listed thermal expansion tanks (listed to ANSI/NSF 61) and Watts “LFBR” combination ball/relief valves (IAPMO Listing File #3998). There are also combination toilet fill/thermal expansion relief valves and pressure relief valves available but are not listed by IAPMO.

No. This type of trap seal primer merely diverts non-potable water from the water closet vacuum breaker tailpiece to the floor drain tailpiece. The overflow rim of the water closet remains a minimum of 6 inches from the critical level of the vacuum breaker, per Section 603.5.1 of the 2015 Uniform Plumbing Code, while the flood rim of the floor drain exceeds the 6 inch requirement from the vacuum breaker, as found in Table 603.2.

1. Section 604.1 of the 2018 Uniform Plumbing Code (UPC) requires materials used in the water supply system, except valves and similar devices, to be of like material unless approved by the AHJ. This dissuades the use of multiple materials such as copper, galvanized and plastic in a single water supply or distribution system. In the event that the AHJ has allowed the use of multiple materials in a water supply or distribution system, Section 605.16, gives specific requirements as to the types of transition fittings that may be used to connect dissimilar materials.
2. Per Section 605.16.1, “joints from copper or copper alloy pipe or tubing to threaded pipe shall be made using copper alloy adapters”. Copper alloys are metal alloys that have copper as their principal component. Brass or bronze adapters, are both in the copper alloy family, and would be considered acceptable fittings for transition to dissimilar materials.

1. The standard referenced in the 2012 Uniform Plumbing Code(UPC), for the testing and listing of Press or Nail type copper alloy fittings, is IAPMO PS 117-2008(Copper and Copper Alloy Tubing System Incorporating Press-Type or Nail-Type Connections). This standard may be found in Chapter 14 (Referenced Standards).
2. Section 301.2 requires all pipe, pipe fittings, traps, fixtures, material, and devices used in a plumbing system to tested and listed to applicable standards found in the code. IAPMO PS117-2008, found in Chapter 14, is the standard used for the testing and listing of copper alloy press or nail type fittings used in potable water systems.

*Note: ASME B16.51-2013 (Copper and Copper Alloy Press-Connect Pressure Fittings) was included in Table 604.1 of the 2015 UPC. Both ASME B16.51 and IAPMO PS117 are referenced in Chapter 6 and/or Chapter 17 of the 2015, 2018 and 2021 editions of the UPC.

1. Table 604.1 of the 2018 Uniform Plumbing Code(UPC)lists ASME16.51(Copper and Copper Alloy Press-Connect Pressure Fittings) as a required standard for the testing and listing of press-connect fittings. IAPMO PS 117(Press Connections) is also referenced in Chapter 17, Table 1701.2 as an applicable standard for these types of fittings.
2. Standards for specific products may be referenced in multiple locations within the Code. They may be incorporated as part of a particular Code section, listed in applicable tables, or both.

Yes. The requirements found in Section 609.2 of the 2009 Uniform Plumbing Code (UPC) refer to the separation, in a single trench, of a potable water supply and building sanitary sewer. The 2009 UPC does not restrict the installation of storm water piping or a catch basin from being installed over or near a potable water line.

1. All flexible water connectors*, including braided and corrugated types, must meet the requirements found in ASME A112.18.6/CSA B125.6-17 and be readily accessible**, per Section 604.5 of the 2015 Uniform Plumbing Code. Section 604.12 merely addresses length limitations for flexible “corrugated” connectors.
2. No. The submitted installation is accessible, but is required to be readily accessible.

*ASME A112.18.6/CSA B125.6-17 Flexible Water Connectors
Section 3.1 Definitions
Flexible water connector (flexible connector) — a non-rigid tube or hose with end connections used for connecting a water supply to a fixture, fitting, or appliance.
** 2015 UPC
Section 203.0 Accessible, Readily. Having a direct access without the necessity of removing a panel, door, or similar obstruction.

1. Yes. The term appliance, referenced in Section 606.5 of the 2015 Uniform Plumbing Code, is a plumbing appliance as defined in Section 218.
2. No. By definition, tub/shower valves, hose bibbs, washing machine stops, etc. would be considered fixture fittings*.
3. Per Section 606.5, parallel water distribution systems are required to have a shutoff valve for each fixture or appliance either at the manifold or at the fixture or appliance. When manifolds are located in areas that are not readily accessible, a valve is required at each individual fixture or appliance. When installing a parallel water distribution system, a valve is required on every fixture or appliance, regardless of the type of joint used to connect the fixture or appliance to the water distribution system.

*Section 208.0 Fixture Fitting – A device that controls and guides the flow of water.

1. No. The intent of Section 605.3 of the 2009 Uniform Plumbing Code, is to provide a means of shutting off the water to a single dwelling unit without disrupting the water supply to other dwelling units. This can be accomplished by installing a shutoff valve at the water distribution line(s) to each dwelling unit or by installing individual shutoff valves at each fixture and water fed appliance within the unit.

Acceptable methods to relieve thermal expansion, per Section 608.3, are listed thermal expansion tanks (listed to ANSI/NSF 61) and combination ball/relief valves (IAPMO Listing File #3998). There are also combination toilet fill/thermal expansion relief valves and pressure relief valves available but are not listed by IAPMO.

No. Section 602.2 (Cross Contamination) of the 2018 Uniform Plumbing Code states that “…each point of use shall be separately protected where potential cross-contamination of individual units exist”.

1. Yes. An ASSE 1035 laboratory faucet backflow preventer consists of two independently acting check valves with a means for automatically venting to the atmosphere between the check valves. An air gap, as specified in Table 603.3.1 of the 2021 Uniform Plumbing Code (UPC), would be required to prevent the possibility of the atmospheric port* on the ASSE 1035 device from being submerged in contaminated waste water.
2. The air gap would have to meet the requirements found in Table 603.3.1.
3. No. Section 603.5.7 applies to outlets with hose connections, such as freeze-less yard and wall hydrants and hose bibbs.

*603.4.9 Prohibited Locations. Backflow prevention devices with atmospheric vents or ports shall not be installed in pits, underground, or submerged locations. Backflow preventers shall not be located in an area containing fumes that are toxic, poisonous, or corrosive.

There are two issues at hand:

1. The installation of any device which prevents the dissipation of building water pressure back in to the water main requires the installation of an (listed and adequately sized) expansion tank or similar approved device. The device must be installed on the building side of the double check valve, backflow preventor or other device and must be sized in accordance with manufacture’s installation standards.
2. Any storage water heating equipment must be provided with an approved, listed and adequately sized combination temperature and pressure relief valve. Exception: a listed non-storage instantaneous water heater with an inside diameter less than 3 inches, however, overpressure protection must be provided by means an approved pressure relief valve. The pressure relief valve must be installed to its’ listing and the manufacturer’s installation instructions.

1. Under section 602.3, Backflow Prevention, a backflow device is required to protect the potable water supply if there is any possibility of pollution or contamination from a water treatment system. A water treatment device connecting directly to the potable water supply which potentially introduces contaminates and/or pollutes a potable water supply system, shall be protected by the appropriate backflow protection as specified in Table 603.2. If the water treatment system utilizes a discharge line into a drainage system, the discharge shall be through an air gap, potentially in addition to a backflow prevention device.

2. Determining the potential for contamination or pollution and/or backflow requirements should be through applicable standards and manufacturers product information. Check with Authority Having Jurisdiction.

Pollution is defined by Section 218.0 as an impairment of the quality of the potable water system to the degree that does not create a hazard to the public health, but which does adversely and unreasonably affect the aesthetic qualities of such potable water for public use. Also defined as “low hazard”.

Contamination is defined by Section 205.0 as an impairment of the quality of the potable water system that creates a hazard to the public health through poisoning or the spread of disease by sewage, industrial fluids, or waste. Also defined as high hazard.

Yes. This device can be used. Provided that after installed the device can not be removed.

1. Yes. Section 601.2 of the 2015 UPC specifically states, “In occupancies where plumbing fixtures are installed for public use*, hot water shall be required for bathing and washing purposes”.
2. Yes
3. Per Section 407.3, “hot water delivered from public-use lavatories shall be limited to a maximum of 120°F by a device that is in accordance with ASSE 1070 or CSA B125.3”.

* Public or Public Use. Applies to plumbing fixtures that are not defined as private or private use.
Private or Private Use. Applies to plumbing fixtures in residences and apartments, to private bathrooms in hotels and hospitals, and to restrooms in commercial establishments where the fixtures are intended for the use of a family or an individual.

Section 608.5 of the 2015 UPC addresses the discharge piping for temperature relief valves, pressure relief valves or combinations of both. Relief valves are required for a multitude of plumbing and mechanical appliances, including but not limited to water heaters and boilers. Domestic water heaters are equipped with temperature and pressure reliefs valves set at 210°F and 150 psi pressure. The discharge piping therefore must be tested and listed to withstand temperatures of a minimum of 210°F.

1. Yes. Rolled and cut grooved mechanical joints may be installed underground and concealed in walls. These types of mechanical joints are considered to be permanent joints and per relevant subsections of Section 605.0 of the 2015 Uniform Plumbing Code, must be installed per the manufacturer’s specifications.
2. No. As stated above, these types of joints are considered to be permanent joints and unlike slip joint do not need to be accessible.

1. No. The minimum wall thickness of PVC pressure water piping, per ASTM D1785, is Schedule 40. Section 605.12.3 of the 2015 Uniform Plumbing Code, gives requirements for both Schedule 40 and 80 PVC pipe. When mechanically threading PVC pipe the minimum wall thickness of the material is Schedule 80. When Schedule 80 PVC is threaded, the pressure rating of the piping must be reduced by 50 percent.
2. Yes. Per Section 605.12.3, molded threaded PVC fittings may be used without a reduction in the pressure rating of the pipe.

Yes, Section 603.4.3 of (2015/2018/2021)The Uniform Mechanical Code applies to any testable backflow prevention devices installed exceeding 5’ above floor or grade. The platform will ensure some safety for the person who might have to install, test and maintain the device.

A closed water distribution system having a check valve, pressure regulator, backflow preventer or other device that prevents pressure buildup in the building from being able to dissipate back into the source or water supply main regardless of the type of water heater used, must be equipped with an expansion tank or other means to control the thermal expansion pressures.

Yes, if the mechanical tees are listed for the application and if the listing is adopted or as stated above is a recognized standard in the code. The local AHJ should be consulted prior to installation as prescribed in Section 301.2, Minimum Standards.