When it comes to radon vent pipe clearances it can be confusing what is and what’s not allowed, what’s safe and what is not. Looking at radon mitigation systems in central New York you will see a wide range of installation methods including the location of radon vent pipes. Very often radon system installations do not follow the EPA or similar radon mitigation standards.
There are several reasons for this confusion including:
- Some radon mitigators install the quickest cheapest system possible disregarding all radon mitigation standards.
- Many parts of country have no codes or regulatory oversight regarding radon mitigation.
- Areas where radon mitigation falls under the building codes there is often confusion due to lack of education on the part of code enforcement.
- Many code enforcement officers simply don’t have time to inspect radon mitigation systems, unless complaints are filed.
- Building codes change from year to year.
- Some of the radon mitigation standards are considered outdated by some radon mitigators and radon supply manufacturers.
Some states are just beginning to look at implementing codes and educating code enforcement officers for radon mitigation including New York State. The EPA and other guidelines somewhat follow the standard codes for plumbing vent pipes which generally are vented above the buildings roof. New York State just raised plumbing vent pipe code from 12 inches to 18 inches above the roof and at least 10 feet horizontal distance from any opening to the building i.e. window or fresh air intake. The EPA radon mitigation standards are pretty general designed to cover a wide range of building situations.
Radon Vent Pipe Clearances – Example
In following scenario, following the EPA standards it would be fine for a small single story house 1.) to be vented above the roof line as close to the ridge as possible, 2.) terminating at least 10 feet above the ground. This would be considered safe even if there may be a high rise building right next door with windows and balconies many stories high with the closest window only 10 feet and 1 inch horizontal distance away from the radon vent termination and with many more windows above that. This scenario would meet the EPA safety standard for the high rise occupants, figuring that the radon laden air would dilute to a negligible amount after traveling less than 10 feet.
Practical Application of Safe Radon Vent Pipe Clearances
So practically speaking, if there are no specific codes that require otherwise, in the above high rise scenario those same clearances should be perfectly safe to apply regarding your own home. As long as you meet the safety distances from openings to the building and direct the radon gas away from the home so as not to cause moisture damage, in some situations it may be preferred not to vent above the roof line.
Practical example: Lets say a radon system is located on downwind gable end of a 2 level home and the height of the roof ridge is 35 feet above grade and there are no windows at all on the entire wall. By the way this is a fairly common situation I run into. Say there is an exterior chimney on the center of that wall and you want to run the radon vent pipe on the rear side of the chimney so it is not seen from the road. It should be “safe” to terminate the radon pipe 15 or 20 feet above the ground (which exceeds the 10 foot minimum height standard). It is also well over 10 feet horizontal distance from any windows or vents to the sides or above including any soffit vents that may be present. Even though the radon pipe does not extend “above the roof as close to the ridge as possible” it discharges the radon gas in a safe way, while reducing the vent height by 15 to 20 feet. In this example, even though it does not technically adhere to the EPA radon mitigation standards, it does adhere to the heart of the safety issue. It also has the benefit of shorter vent height which will improve the performance of the system and make it easier and safer to maintain and service, verses running the pipe another 15 or 20 feet to meet the letter of the EPA standard.
In this photo to the left you can see a radon vent pipe that terminates safely about 13 feet above the ground and greater than 10 feet horizontal and 2 feet above the closest window. The top of the vent is angled at 45 degrees to the moist air does not cause moisture damage or mildew stains on the siding. This homeowner preferred this installation verses running the vent up the soffit, around the gutter and above the roof.
Below are some pros and cons pertaining to radon vent pipe clearances explained that should help you in determining what might be best for your specific situation. I like to weigh out all the options, talk it over with the homeowner and decide what will work best for their needs.
Advantages of shorter radon vent pipes when safely installed:
- Shorter pipe is easier to install and saves on cost.
- Shorter pipe makes it easier and safer to maintain vent and change radon fan when needed.
- Shorter pipe will have less condensation and related freezing issues that can hinder fan performance and shorten fan life.
- Shorter pipe will have less resistance which leads to better fan performance and lower radon level.
- In many situations a shorter pipe will look better aesthetically.
Disadvantages of shorter radon vent pipes:
- The shorter the pipe the louder the air discharge noise, this can sometimes make a difference.
- If it terminates lower than 10 feet above the ground it could be a potential safety hazard.
- If it terminates less than 2 feet above a window within a 10 foot horizontal distance it could be a potential safety hazard.
- If it terminates less than 10 feet horizontal distance below a window it could be a potential safety hazard.
- If it terminates less than 10 feet horizontal distance below a ventilated soffit or other air vent it could be a potential safety hazard.
Including contractors who say they strictly adhere to the EPA Mitigation Standards of Practice it is very rare that any radon mitigation contractor will run the vent pipe up the center of a gable wall in order to terminate the vent pipe above the roof as close to the ridge as possible – as per the EPA standards. I explain the practical and safe application or radon vent pipe clearances and if that is what people want, I will be happy to do that. They may want to be extra safe, but at the same time I explain it will be more difficult to service, less aesthetically pleasing, and sometimes may cost more.
A shorter pipe can usually be easily extended if decided at a future date to vent higher up above the roof.
Side wall venting. Many gas appliances vent through side walls now instead of chimneys. One of the newest fans designed specifically for radon mitigation vents directly through the side wall similar to a dryer vent, using an aspiration hood to mix and disperse the radon gas; it follows the same clearances as high efficiency gas fired heating appliances that also vent through side walls, they are allowed to at least 4 feet directly below a window opening. Additional clearances to doors and vents also apply similarly to the gas appliance sidewall exhaust vents.