Eliminates the need to repair/replace trap primers when they fail. Retrofit: Used in situations where trap primers have failed or where trap primers were never installed. The SureSeal floor drain trap sealer can be used with all 2”, 3”, and 4” floor drains and in 3 ½” & 4” floor drain strainers. A Primer on “S” Traps By Reuben Saltzman In 'S' Traps, Plumbing On June 5, 2012 A common plumbing defect found in many older houses is an “S” trap.
A trap primer (or trap seal primer) is a plumbing device or valve that adds water to traps. The water seals in traps are needed to prevent sewer gases from entering buildings, but because this water is exposed to the air, it is subject to evaporation over time in infrequently used floor drains, leading to the release of sewer gas into the environment. The trap primer mitigates this problem by injecting water, either directly or indirectly, into the trap to maintain the water seal indefinitely.
Building codes may require trap primers for traps in certain locations or situations, usually those in which industry experience has shown that they are likely to dry out. The most common requirement is for basement floor drains, which are only used when the basement floods. Sometimes they are also installed in locations where the plumbing code does not require a primer because of a high probability of the trap drying out, but because of a nearby ignition source and the explosion hazard in the event that the trap did leak sewer gas. Most designs require installation in an accessible location where periodic maintenance can be performed.
Types[edit]
There are many types of trap primers. The simplest, typically for a floor drain's trap, is simply a connection from a nearby sink's drain so that when the sink is used, some of the water flow is diverted into one or more traps. More common is a primer that is connected to the potable water supply and activates when pressure fluctuations are sensed, such as the flushing of a nearby water closet. Others depend on occupancy sensors or timers.[1] Several manufacturers (e.g., Moen) produce laundry faucets with a built-in trap seal primer outlet.
Other solutions[edit]
In infrequently used floor drains where such a primer does not exist, evaporation can be mitigated a few different ways:
- Routinely adding water to the floor drain
- Pouring a small amount of vegetable or mineral oil into the drain to just cover the trap's water surface. The oil floats on the surface of the water and creates a liquid seal preventing further evaporation. Mineral oil tends to be a better option, as it does not go rancid, where vegetable oil does. Any environmental impact from its discharge is negligible compared to the contents that can be flushed out of a flooded basement.
- Using a propylene glycol solution instead of water in a trap. Raising the boiling point of a solution is equivalent to reducing its vapor pressure, and consequently its evaporation rate. This also protects the trap against freeze damage. The glycol attracts water, and so maintains a minimum concentration which depends on the humidity or water vapor pressure in the air. Unlike ethylene glycol, common automotive antifreze, propylene glycol is non-toxic.
- The evaporation rate of a liquid is directly proportional to its vapor pressure. At 25 °C the vapor pressures for water, pure propylene glycol and pure mineral oil are, consecutively, 24 torr,[2] 0.1 torr[3] and <0.01 torr.[4] Be aware though that the properties of 'RV antifreeze' which has propylene glycol in it will be different than pure propylene glycol because alcohol, water and other ingredients are in it. One manufacturer of RV Antifreeze gives the vapor pressure of their product as 17 torr at 20 °C.[5] This material, if placed in a drain, will evaporate almost as fast as water. Some makers of RV Antifreeze will list the vapor pressure of their product as 0.1 or <0.1 torr. This however is only for the propylene glycol component, not the mixture that comprises their product which can be mostly water.
- Check valves designed as 'inline trap sealers' are permitted by many local codes. The SureSeal [1] is a gravity-mechanical type; the Trap Guard [2] is a duckbill type.
Poor plumbing vent design or extra windy conditions affecting vent pipes can also cause water seals to be siphoned or blown out of traps.
References[edit]
- ^'Trap Seal Primer Selection Guide'(PDF). www.mifab.com. MIFAB. 2014. Retrieved 1 March 2016.
- ^Vapour pressure of water
- ^File:LogEthyleneglycolVaporPressure.png
- ^http://www.arb.ca.gov/db/solvents/solvent_pages/Hydrocarbon-HTML/Mineral_Oil.htm
- ^Duramax 50 RV Antifreeze Material Safety Data Sheet
See also[edit]
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Trap_primer&oldid=711483366'
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Plumbing drain traps:
This plumbing traps (interceptors) article describes plumbing traps (interceptors) and how to diagnose, find, and cure odors in buildings including septic or sewage or sewer gas smells or 'gas odors' in buildings with a focus on homes with a private onsite septic tank but including tips for owners whose home is connected to a sewer system as well.
We describe the common problems that occur at plumbing traps: odors, leaks, noises, and we discuss plumbing trap types, requirements, locations, connections, installation, repair and replacement. This article distinguishes between P-traps and older S-traps and explains trap siphonage and the dangers that can result from dry plumbing traps.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Problems With Plumbing Fixtures or Fixture Traps (Interceptors) & Sewer Gas Leaks & Odors
A plumbing trap is a U-shaped bent building plumbing drain component whose job is to maintain a water seal to keep sewer gases from rising back up into the building from the building's sewer drain piping system.
Watch out: Improperly installed, damaged, leaky, or missing plumbing drain traps can release smelly and even dangerous sewer gas odors in the building.
[Click to enlarge any image]
Our photo (left) shows a plumbing trap that was abandoned in a building basement. The chopped-off, open drain line combined with eventual dry-out of the water in the plumbing trap shown will provide a ready path for sewer gases to enter the structure - a sanitary hazard and even an explosion hazard.
This article series describes both plumbing drain traps and how properly-installed traps or interceptors should prevent or cure sewer gas odors from septic systems, building plumbing, & similar sources.
Checklists in this article series will help with sewer gas smell diagnosis or septic gas smell diagnosis. Other causes of sewage odors, septic odors, sewer gas, rotten egg, or other indoor gas odors are also described.
The page top sketch of the detailed parts of a plumbing trap was provided courtesy of Carson Dunlop Associates, a Toronto home inspection, education, & report writing company.
Clogged Plumbing Traps / Interceptors
Clogged or blocked plumbing traps can cause leakage, and organic debris in plumbing traps may itself be a source of odors which people mistake for sewer gas backups.
If your drains are slow at only certain fixtures one of the first things to check is for clogging of the individual fixture traps.
As Carson Dunlop's sketch shows, some fixtures such as laundry sinks are required to have traps which include a cleanout plug, making cleaning of the trap easier.
Otherwise you'll have to remove the entire plumbing trap to clean it.
(Remember to put a bucket under a trap before trying to remove it, and remember not to try working on plumbing traps on Sunday night when you can't dash out to the building supply store to replace parts you've broken.)
Definition: What's the difference between Plumbing Traps vs Plumbing Interceptors?
Note: recent changes in plumbing codes including ASME Standards, the Uniform Plumbing Code (UPC), Canadian Standards Association (CSA) and the International Plumbing Code (IPC) have dropped the term plumbing trap, and substitute a more inclusive word, 'interceptor'.
So what's being 'intercepted'?
In this usage, sewer gases are 'intercepted' or prevented from entering the building from the drain system.
In some building codes and plumbing texts you will see increased use of the term interceptor where you may be more familiar with the term plumbing trap.
In particular, grease traps are referred to now as hydromechanical grease interceptors or gravity grease interceptors.
Causes & Cures for Dry Plumbing Traps / Interceptors & Dry Plumbing Trap Odors
Definition of Dry Plumbing Traps: a dry trap is a plumbing trap or interceptor that has lost its water seal, thus permitting sewer gases to escape back up building drain piping and out into the building through the fixture - an unsafe, unsanitary, and potentially dangerous condition.
When a plumbing trap remains un-used for a long time the water can simply evaporate from the trap, permitting sewer gases to back up into the building.
Watch out: Because sewer gas contains methane gas (CH4) there is a risk of an explosion hazard or even fatal asphyxiation.
See ODORS, DRAIN & SEWER LINE SOURCES and also DRAIN PIPING & SEWER ODORS
and also see METHANE GAS SOURCES
![Primer Primer](/uploads/1/2/4/7/124726247/990712193.jpg)
Some places where we often find dry plumbing traps include:
- Un-used basement plumbing fixtures like laundry sinks or basement bathrooms
- Basement floor drains often become sources of sewer odors because they remain unused and dry out.
See FLOOR DRAIN / TRAP ODORS - Backdrafting caused by exhaust fans used in tight buildings can sometimes both draw sewer gases out of a dry plumbing trap or other drain piping leaks and may move such odors through the building.
See BACKDRAFTING & SEWER/SEPTIC ODORS
Watch out: backdrafting in buildings is more than a bad smell problem as it may cause unsafe back-drafting of combustion products and carbon monoxide into the occupied space - potentially fatal hazards. - Buildings left unoccupied for months,permitting the water in other traps to dry out
- Buildings in which plumbing traps are leaky, thus losing their water seal even over just a short time
- Buildings in which the plumbing vent system is incomplete, missing, or improperly constructed. Improper plumbing vents or absence or clogging of a vent system can cause plumbing trap siphonage: water flowing down the building drain line can siphon or 'pull' the water seal out of plumbing traps.
See PLUMBING VENT DEFECTS & NOISES
Remedies for Dry Plumbing Traps
There are various ways to deal with dry plumbing traps to stop smelly and dangerous sewer gas backups into the building. These include
- Use of self-sealing traps
- Pour clean mineral oil into the trap when the building is to remain unoccupied for a month or longer. Simply pouring enough clean mineral oil into the trap to fill the trap bottom is an effective preventive measure and mineral oil in small quantities won't harm a septic or sewer system. Mineral oil will not evaporate, even over months of trap disuse.
- Pour food-grade antifreeze into the plumbing trap. When winterizing a building where traps are left in place they may be filled with food-grade antifreeze.
- Use o a trap primer to keep a water charge in the plumbing trap. Carson Dunlop Associates' sketch at above left shows how a trap primer system can be installed from a laundry tub.
Self-Sealing Traps for Floor Drains
Self-sealing plumbing traps (interceptors) containing check valves are available and are suited for floor drains. If water on the floor needs to escape it can flow out of the trapped floor drain, but the trap contains a mechanical seal which prevents sewer gas backups even if the floor drain trap is dry.
Leaky Plumbing Trap or Interceptor & Other Defects
Our explanation of plumbing trap (interceptor) leaks has moved to
Loose Toilets Can Produce Sewer Gas Odors Indoors
Why sewer gases may leak into a building at the toilet
There is no actual plumbing trap in the waste pipe immediately below a toilet.
Toilet bowls are themselves in effect the largest plumbing trap in most buildings. The water in the toilet bowl is providing the trap seal that prevents sewer gases from rising up the drain piping and exiting through the toilet base into the building.
So if the toilet bowl is dry - from many months of no use (or more rare, from leaks at a cracked toilet bowl) then sewer gases can indeed enter the building through the toilet. We might prevent this hazard at an un-used toilet by pouring clean mineral oil into the toilet bowl just enough to fill the bottom trap weir.
But toilets can still leak sewer gases into a building if the toilet is or has been loose or if the toilet base was not properly sealed to the waste pipe.
Check your toilets for leaks at the toilet base.
The wax ring used to seal the toilet base to the waste pipe at the floor may be deteriorated or leaky, especially if the toilet is loose or was previously loose.
A wobbly toilet compresses the wax ring seal, leading to leaks and sewer gas odors in the bathroom.
In the photograph shown here, stains around the toilet base suggested that this toilet had been leaking at its base - a condition both unsanitary and smelly.
A wobbly toilet compresses the wax ring seal, leading to leaks and sewer gas odors in the bathroom.
In the photograph shown here, stains around the toilet base suggested that this toilet had been leaking at its base - a condition both unsanitary and smelly.
How to check for a loose toilet
Straddle the toilet and gently pinch it between your knees. Then gently push on each side of the toilet to see if it moves.
If the toilet moves it may be leaking into the floor (and ceiling below) - an unsanitary condition.
The toilet needs to be removed, any damaged floor repaired, and then the toilet is TOILET is REINSTALLED [photo] using a new WAX TOILET SEAL RING [image] before bolting it securely to the floor.
Details about how to fix a loose or leaky toilet are at LOOSE TOILET REPAIRS.
Plumbing Trap Materials: Metal vs PVC Plumbing Traps & Interceptors
This discussion has moved to PLUMBING TRAP MATERIALS & PROPERTIES.
Plumbing traps are constructed of any of a number of old traditional materials, principally metals, occasionally wood, or of newer plastic materials.
That photo series can identify the type of plumbing trap or interceptor material in a building.
S-Traps on Plumbing Fixtures & Drains
Use of 'S' Traps or other illegal and obsolete plumbing fixture traps where a 'P' trap is required:
S-traps are often installed in older buildings where there is no venting provided for that plumbing fixture.
S-traps easily lose the water from the plumbing trap, especially if the S-trapped fixture is near a toilet or other large plumbing fixture. Carson Dunlop Associates' sketch at left shows several types of illegal plumbing traps including the 'S' trap.
When the larger fixture is draining, the sudden and large volume of water rushing down the drain creates a vacuum in the drain line that can siphon water out of the nearby plumbing traps.
When a plumbing trap has lost its water seal, sewer gases pass readily back into the building.
Look below the sinks for antiquated or un-vented drains - if you see an 'S' trap rather than a modern 'P' shaped plumbing drain trap, the fixture is almost certainly not properly vented.
Details about s-traps are now found at PLUMBING S-TRAP CODES & HAZARDS
Garbage Disposers (food grinders) and Plumbing Traps / Interceptors
Don't forget to check for smells at your garbage disposer drain too.
And in buildings where GREASE INTERCEPTORS TRAPS or grease interceptor is installed, the garbage disposer (food grinder) drainage is required to bypass the grease trap. This requirement is notwithstanding that garbage disposers (and the pre-rinse function of some dishwashers) is a substantial source of fats, oils, grease (FOG) that clog plumbing drain systems.
If that is the odor source you may be able to remove the odor by cleaning liquids or even simple vinegar.
Sewer Gas or Methane Gas Hazards & Plumbing Traps
Smelly and potentially explosive sewer gases are lighter than air and will rise up through plumbing drain or sewer systems unless these gases are blocked from entering the building.
The two principal features that prevent sewer gases from entering a building through its plumbing drain system are water-filled plumbing traps [the blue area of the plumbing trap in our sketch] at sinks and tubs or other plumbing fixtures, and the building plumbing drain vent system [labeled in our sketch] that vents sewer gases above the building roof.
The water trap is critical to keep sewer gases from rising from a sewer or even from a septic system back into the building.
The blue area showing where water rests in the plumbing trap has a maximum allowable height of 4'.
But water must remain in this space to act as a seal.
What makes the smell in sewer gas? Sewer gases are more than an obnoxious odor. The page top schematic of a typical plumbing trap is courtesy of Carson Dunlop Associates'.
Watch out: Because sewer gas contains methane gas (CH4) there is a risk of an explosion hazard or even fatal asphyxiation.
Sewer gases also probably contain hydrogen sulfide gas (H2S) In addition some writers opine that there are possible health hazards from sewer gas exposure, such as a bacterial infection of the sinuses (which can occur due to any sinus irritation).
Depending on the sewer gas source and other factors such as humidity and building and weather conditions, mold spores may also be present in sewer gases.
Technical note on sewer gas smells: because the 'sulphur smell' that some people may associate with dangerous sewer gases can have other sources having nothing to do with building plumbing systems, readers should also see
CHINESE DRYWALL HAZARDS and
ODORS, SULPHUR SMELL SOURCES and
ODORS, SEPTIC or SEWER and finally,
ODORS GASES SMELLS, DIAGNOSIS & CURE where we describe how to track odors to their source or cause.
...
Continue reading at PLUMBING TRAP LEAKS & MISSING INTERCEPTORS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see PLUMBING DRAIN NOISES where we explain the basics of proper plumbing vent piping and how errors cause trap siphonage, odors, and noises
PLUMBING TRAP, INTERCEPTOR FAQs - questions, answers, comments posted originally at this article
PLUMBING VENT DEFECTS & NOISES - home
Or see this
Article Series Contents
- PLUMBING TRAPS & INTERCEPTORS - home
Suggested citation for this web page
PLUMBING TRAPS & INTERCEPTORS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.
INDEX to RELATED ARTICLES: ARTICLE INDEX to PLUMBING SYSTEMS
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Technical Reviewers & References
- 'Guidance Document for Sizing and Installation of Grease Traps and Interceptors', Carrolton Texas, January 2012, retrieved 2/16/2014, original source: http://cityofcarrollton.com/Modules/ShowDocument.aspx?documentid=8181
- Kia Gregory, 'New York Tries to Clear Its Sewers of FOG (Fat, Oil, and Grease)', The New York Times, p. A18, 15 February 2014
- Thanks to Slade Franklinfor the reminder that a leaky wax ring at a toilet can lead to septic odors in bathrooms. 11/2007
- Thanks to J.V. (privacy protected) for the reminder to make a detailed inspection of the plumbing vent system when sewer gas odors are present. 07/2008
- Thanks to Roger Hankey & Cheryll Brown, www.hankeyandbrown.com, ASHI home inspectors in Minnesota, for the deteriorated transite pipe gas flue vent photograph and comments. Mr. Hankey is a past chairman of the ASHI Technical Committee, serves as co-chairman of ASHI legislative committee, and has served in other ASHI professional and leadership roles. 7/2007.
- Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
- Steve Smallman, Raleigh, NC, Email: [email protected], Website: http://stevesmallman.com/ - Quoting: Steve Smallman Property Inspections (SSPI) inspectors have performed or supervised over 25,000 inspections since we introduced home inspections to the Triangle area in 1980. Mr. Smallman is a contributor to InspectApedia.com and has commented on or provided information on plumbing traps, commercial FPE electrical panels and DIY Tests of FPE equipment, roofing underlayment, and building exteriors.
- PLUMBING DRAIN NOISE DIAGNOSIS: may indicate defective or clogged plumbing: how to diagnose and cure drain sounds
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