September 3rd, 2010 | Hydrogen Sulfide Gas Articles | No Comments »
Every state, city, and village either has odor ordinances or treats obnoxious odors perceptible beyond property lines as public disturbances/nuisance. All plumbing vent stacks produce odors unless they fitted with a filter. OSHA warns that levels of 300-ppm (H2S) cause the olfactory nerve to lose sensitivity. At first a “rotten egg” odor is detected but on the second or third breath the odor is no longer noticed. All major odor problems have associated fines or other penalties.
When you are experiencing sewer or septic smells inside a home or business not near a plumbing fixture these odors are most likely coming from your sewer vent stacks on your roof. All plumbing vent stacks produce odors including that “rotten egg” smell caused by hydrogen sulfide gas unless they are fitted with a filter. One of the most common problems is the sewer gas (H2S) is drawn into the fresh air intakes on the roof from the air conditioning systems. On roofs industrial buildings code also require fresh air intake for building air balance against all the stale air exhausted through roof vents. The potential problem can be identified through basic smell of odor when on the roof or around the perimeter of the building as hydrogen sulfide (H2S) gas is heavier than air and thus falls to “nose level” quickly when the wind blows just right. A professional can use a H2S measuring device to detect and measure sewer gas concentration being omitted from specific roof vent stacks. The vents omitting gas is a natural occurrence on most homes and buildings because that’s the way they are designed.
Raising roof vent stacks does not solve the problem it only displaces it on a windy day to blow over the exterior wall to open windows, the patio, the fireplace, the garden, pool area, sidewalk, front door, driveway, or parking lot. On a non-wind day sewer gas is heavier than air and will settle on roof and cause intermittent sewer odors in the home or building.
Installing a One way valve on the sewer stacks will reduce the sewer gas that vents to the roof through the opening and closing of the valve. The Mechanical Engineers design the sewer venting system for it to be a sealed system in the home or business but unrestricted venting to the atmosphere. This type of system defeats the original design intent for all building designs. The system operates on demand of actions in the home or business such as the flush of a toilet or turning on a sink. Since this type of system is capping the vent stacks, it is pressurizing the sewer system in the home or business. It is creating more of a potential for sewer gas odor problems. Any type of bad plumbing seals or gaskets that that may have a small leak will cause the problem to intensify. The vent is now mechanically opened and closed by a valve. It can fail in open position too. This introduces sewer gas to the roof, when it fails.
Charcoal vent stack filters on the sewer stacks is one odor filters on the market but is less effective when introduced to moisture which causes it to solidify or cake up. Sewer gas from the vent stacks is extremely high with moisture since the systems primary function is to drain water in a sealed system underground away from the building. In my opinion this product is not the right product for this application.
I recommend for homes odor eliminator vent stack filters that use Zeocarbon. Zeocarbon is a mixture of carbon and zeolite rock, which has been independently demonstrated to work up to 7 times longer than regular carbon alone. Vent stack filters using this technology are unique in that they actually regenerate themselves for up to 5 years. These systems use sunlight. The exterior, interior, and zeocarbon replaceable bags themselves are impregnated with titanium dioxide (approximately the same quantity and type in most popular toothpastes on the market). When exposed to direct sunlight the titanium dioxide produces ozone, which directly destroys odors and regenerates the zeocarbon. When combined with “no flow periods” common to most households, this design allow us to operate up to 5 years without refilling the units. Many units completely block any regenerative UV sunlight though the use of opaque rain caps and guards that promote the development of odor producing bacteria. However because the zeocarbon can only absorb so much gas, this type filter is designed with a low cost, easily replaceable insert bags. Another good thing on this type filter is the restriction on the airflow is so slight (it has a pressure differential measured at only 1.5″ w.g./ft@50 fpm) that it does not interfere with normal venting of the plumbing system. This type filter is made with animal resistant self-cleaning screens coupled with the frost proof insulating solar heat absorption design characteristics, protects the vent stack from plugging in all seasons.
The zeocarbon filter not only traps sewer gases at the roof vent, so they cannot escape into the air at all, but it also means less air pollution from GREENHOUSE GASES. It particularly traps ammonia, carbon dioxide (global warming) and hydrogen sulfide (the rotten-egg smelling gas), which the filter traps on an 18-24% wt/wt basis, and used zeocarbon acts as an excellent source of nitrogen when mixed with soil. Even though the filter is installed directly on the vent pipe, it’s frost proof design is such that it not only does not impede air being drawn into the vent, it prevent hoar frost plugging and keeps out insects and critters. This filter is also for vents that are directly connected to aerated or non aerated septic tanks, septic mounds, drain fields, landfill vents, compost vents, etc. In many instances, city-sewer connections bring gas into the home’s plumbing vents which vent the gases out the roof vent and often down into the back yard where they can be drawn into the home. This type filter has proven beneficial in those cases too!
I recommend for mobile homes, resturants, daycare centers, nursing homes, and schools, odor eliminator vent stack filters that filter the harmful sewer odors by oxidation. Oxidation is accomplished with chlorine dioxide technology. Because chlorine dioxide reacts selectively and primarily with only the most offensive odor producing compounds (hydrogen sulfide, organic sulfurs, organic amines) the Odor Eliminators will normally provide a much longer service life than products such as activated carbon. With a properly designed filter that allows the original design of the system plumbing system to function does not pressurize the lines like some of the other products on the market. Moisture does not have a negative effect on the Eliminator therefore unwanted reactions do not occur and power is not needlessly spent allowing chlorine dioxide to be available and ready on demand. The result is safe, extremely effective, broad-spectrum malodor control. Chlorine dioxide remains available and ready on demand.
Polishing is accomplished with technology that protects against the escape of malodors can not be oxidized. It incorporates polymeric adsorption and electrostatic bonding technologies. Polishing and oxidizing are accomplished simultaneously. The result is safe (utilizing the same material approved for food storage by the USDA), extremely effective, broad-spectrum malodor control. (Request Form No. 502 from USDA for more detailed information.)
After you have installed roof stack vent filters, inside odors are most likely coming from leaking wax seals or gaskets on your plumbing fixtures. In this case the odor is concentrated typically in an isolated area, the bathrooms. It can be intermittent due to several building mechanical system designs. Bathroom fixtures have a p-trap built-in the fixture so if the fixture becomes loose from the floor or the wall the wax seal or gasket can leak. This type of leak will allow sewer gas to leak directly into the room. Most bathrooms have an exhaust fan which intensifies the introduction of the gas into the room by pulling the gas from the source, the leaking seal at the floor moving it to the ceiling exhaust vent prior to exhausting the gas from the space. This condition is detected through smell or a professional can use a H2S measuring device to detect and measure sewer gas concentration. The remedy for this problem is to replace the bad fixture seals. Contact your preventive maintenance group or to arrange for a local technician help with this problem.
Bathroom odors can also be traced to urine absorption into the tile or tile grout.
Many businesses try to mask the odor by installing a deodorizer mister in the bathroom to spray a scented to product to mask the odors in bathrooms. With proper maintenance of fixtures in the bathrooms and the correct initial designed systems operating correctly this problem should be eliminated. If this condition is corrected overtime it can worsen and affect other parts of the business.
Odor and constant smell can be due to the build up of urine saturating tile grout around urinals and tile grout. There are spray products that eliminates this problem by using it in a regular maintenance program.
When you have floor sinks, drains and floor / wall clean outs dry of water especially in basements of homes and businesses in the production or mechanical areas you will often detect an offensive odor. A dried out p-trap allows the sewer system to vent freely into the space. In the case of a restaurant or any building with an exhaust system that may be in a negative air balance the problem is intensified. The exhaust system can draw the sewer gas into the facility. The affect on an isolated area is not uncommon or if it is near a return on the HVAC system circulate it through out the building. The most efficient way to identify if you have this problem is to do a smoke test on the sewer system. Prior to doing the smoke test we would first recommend verifying all floor sinks and drains have water in the p-traps. This would include the units in isolated rooms such as the mechanical areas and the units installed behind or under equipment. The wall clean outs can be visually inspected but are difficult to detect leakage without a H2S meter or a smoke test. The dried out p-trap when identified can be fixed by adding water to fill the p-trap. Contact your preventive maintenance group to help with this problem.
To fix floor drains and floor sinks add water to the traps on a regular basis or add a trap primer to the system.
To fix floor and wall clean outs check for bad seals in a random fashion. Replace where worn.