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Expansion tank
- Thread starter jmc
- Start date
Frank
Registered User
They are required when there is a check valve in the supply line like a footvalve on the well or some water meters with integral backplow devices.
This language originated in the 2006 IRC
IPC-- 2012
607.3 Thermal expansion control.
A means of controlling increased pressure caused by thermal expansion shall be provided where required in accordance with Sections 607.3.1 and 607.3.2.
607.3.1 Pressure-reducing valve.
For water service system sizes up to and including 2 inches (51 mm), a device for controlling pressure shall be installed where, because of thermal expansion, the pressure on the downstream side of a pressure-reducing valve exceeds the pressure-reducing valve setting.
607.3.2 Backflow prevention device or check valve.
Where a backflow prevention device, check valve or other device is installed on a water supply system utilizing storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
IRC 2012
P2903.4 Thermal expansion control.
A means for controlling increased pressure caused by thermal expansion shall be installed where required in accordance with Sections P2903.4.1 and P2903.4.2.
P2903.4.1 Pressure-reducing valve.
For water service system sizes up to and including 2 inches (51 mm), a device for controlling pressure shall be installed where, because of thermal expansion, the pressure on the downstream side of a pressure-reducing valve exceeds the pressure-reducing valve setting.
P2903.4.2 Backflow prevention device or check valve.
Where a backflow prevention device, check valve or other device is installed on a water supply system using storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
This language originated in the 2006 IRC
IPC-- 2012
607.3 Thermal expansion control.
A means of controlling increased pressure caused by thermal expansion shall be provided where required in accordance with Sections 607.3.1 and 607.3.2.
607.3.1 Pressure-reducing valve.
For water service system sizes up to and including 2 inches (51 mm), a device for controlling pressure shall be installed where, because of thermal expansion, the pressure on the downstream side of a pressure-reducing valve exceeds the pressure-reducing valve setting.
607.3.2 Backflow prevention device or check valve.
Where a backflow prevention device, check valve or other device is installed on a water supply system utilizing storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
IRC 2012
P2903.4 Thermal expansion control.
A means for controlling increased pressure caused by thermal expansion shall be installed where required in accordance with Sections P2903.4.1 and P2903.4.2.
P2903.4.1 Pressure-reducing valve.
For water service system sizes up to and including 2 inches (51 mm), a device for controlling pressure shall be installed where, because of thermal expansion, the pressure on the downstream side of a pressure-reducing valve exceeds the pressure-reducing valve setting.
P2903.4.2 Backflow prevention device or check valve.
Where a backflow prevention device, check valve or other device is installed on a water supply system using storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
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mtlogcabin
SAWHORSE
M2301.2.6 Expansion tanks.
Expansion tanks in solar energy systems shall be installed in accordance with Section M2003 in closed fluid loops that contain heat transfer fluid
P2903.4 Thermal expansion control.
A means for controlling increased pressure caused by thermal expansion shall be installed where required in accordance with Sections P2903.4.1 and P2903.4.2.
P2903.4.1 Pressure-reducing valve.
For water service system sizes up to and including 2 inches (51 mm), a device for controlling pressure shall be installed where, because of thermal expansion, the pressure on the downstream side of a pressure-reducing valve exceeds the pressure-reducing valve setting.
P2903.4.2 Backflow prevention device or check valve.
Where a backflow prevention device, check valve or other device is installed on a water supply system using storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
Expansion tanks in solar energy systems shall be installed in accordance with Section M2003 in closed fluid loops that contain heat transfer fluid
P2903.4 Thermal expansion control.
A means for controlling increased pressure caused by thermal expansion shall be installed where required in accordance with Sections P2903.4.1 and P2903.4.2.
P2903.4.1 Pressure-reducing valve.
For water service system sizes up to and including 2 inches (51 mm), a device for controlling pressure shall be installed where, because of thermal expansion, the pressure on the downstream side of a pressure-reducing valve exceeds the pressure-reducing valve setting.
P2903.4.2 Backflow prevention device or check valve.
Where a backflow prevention device, check valve or other device is installed on a water supply system using storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
Builder Bob
Sawhorse
P2903.4 Thermal expansion control.
A means for controlling increased pressure caused by thermal expansion shall be installed where required in accordance with Sections P2903.4.1 and P2903.4.2.
P2903.4.2 Backflow prevention device or check valve.
Where a backflow prevention device, check valve or other device is installed on a water supply system using storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
If your water meter has a back flow prevention valve installed, A means for controlling thermal expansion may be required on a water heater IF the heating of water contained within causes an increase in pressure........ Some toilets have a burper design, that will allow the excessive pressure to burp or relief into the toilet tank.
A means for controlling increased pressure caused by thermal expansion shall be installed where required in accordance with Sections P2903.4.1 and P2903.4.2.
P2903.4.2 Backflow prevention device or check valve.
Where a backflow prevention device, check valve or other device is installed on a water supply system using storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
If your water meter has a back flow prevention valve installed, A means for controlling thermal expansion may be required on a water heater IF the heating of water contained within causes an increase in pressure........ Some toilets have a burper design, that will allow the excessive pressure to burp or relief into the toilet tank.
Frank
Registered User
In summary Maybe
During the great Virginia earthquake of August 23, 2011 expansion tanks mounted on top of 1/2 inch CPVC pipe with no other support in a multistory assisted living facility caused the largest loss in the county when a few the supporting pipes broke and water cascaded down through 4 stories of units.
During the great Virginia earthquake of August 23, 2011 expansion tanks mounted on top of 1/2 inch CPVC pipe with no other support in a multistory assisted living facility caused the largest loss in the county when a few the supporting pipes broke and water cascaded down through 4 stories of units.
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jar546
Forum Coordinator
Required by code? YES with code sections provided above.Frank said:
Should seismic areas have more stringent requirements, especially due to known history failures? Yes
Is a past bad experience a reason to not require them? NO, just install them so you don't have that problem.
JMHO
The expansion tank requirement for my understand is when you have a storage tank type water heater and a pressure regulator valve on water main which doesn't have integral bypass function, then you do need to install a expansion tank. otherwise NO.
Keystone
SAWHORSE
Its not just a storage tank. When a plumbing system is has a backflow device installed it creates a closed system which necessitates the expansion tank to absorb thermal shock that will occur from typical household fixtures being used. Without the backflow device the entire water system becomes an expansion tank but lacks prevention of the entire water system, in the event your hooked up weed and feed from the garden hose backflows due to a pressure drop in the main or your neighbors house caused by a break.
Frank
Registered User
Water heated from 40F to 150F will expand 2% in volume or 0.8 gallons for a 40 gallon tank. Most plumbing systems without an expansion tank do not have this much air in the system so the water has to go somewhere, out the pressure relief valve or backflowing into the public main. If there is a check valve or PRV on the feed from the source it will open the PRV on a regular basis if an expansion tank is not provided. If there is no PRV and water is not used it will create high enough pressures to burst something as water at normal pressures is essentially noncompressible. 140F water at 5000 psi will only compress 1% over 140 degree water at normal pressure. Heating water from 40F to 140F with a fixed volume would generate around 10,000 psi on the enclosure, which is roughly the peak pressure in a shotgun chamber when it is fired..
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