How To Smoke Test DWV Plumbing Systems
IMPORTANT NOTICE This procedure is provided for general informational purposes only. Smoke testing must be performed only by trained professionals using equipment designed specifically for plumbing smoke testing. Blowfish Smoke Test Solutions assumes no responsibility for improper use of equipment, failure to follow applicable codes, or damages resulting from deviation from manufacturer instructions or local regulations. This procedure does not replace professional judgment or site-specific safety planning.
Site Prep
Notify the owner and occupants of the building being tested.
Ensure no disabled persons or confined pets are on-site who cannot actively avoid smoke. Building should be vacated during smoke testing, except for inspection personnel. Ensure no wastewater will flow through the plumbing system during the smoke test.
Locate the best attachment point. (Figure 1) The objective is for smoke to travel from the blower, past the defect, and exit through the roof vent. To achieve this, position the blower downstream of the plumbing section being tested. Exterior or basement cleanouts are preferred attachment points. Other interior cleanouts and toilet flanges may also be used. As a last resort, the roof vent itself may serve as the attachment point, with smoke exiting into the sewer or through an exterior cap. Use extreme caution when accessing a roof.
If necessary, use pipe plug(s) to isolate the smoke test to a specific area or to prevent smoke from traveling downstream or in unintended directions.
Figure 1
Basement or exterior cleanouts downstream of the test area are ideal attachment points. It is sometimes beneficial to use a pipe plug to ensure all the smoke travels up through the building plumbing and not downstream.
Review venting layout. If attempting to test a system with multiple vents and smoke is not emitting from one or more vents, you may need to:
Relocate your blower attachment point.
Use pipe plug(s) to segment the plumbing and run multiple tests.
Partially restrict vents that are emitting smoke, to direct more smoke to other vents.
Never fully block roof vents - this may prevent smoke from flowing throughout the entire pluming system and create smoke “blow back” at the blower. The goal of a smoke test is NOT to create high pressure, but to allow smoke to flow freely throughout the system. Smoke will naturally escape through defects even under very low pressure. During smoke testing, the total area of smoke egress should be at least equal to the area of ingress.
Disable central station fire alarms to avoid false alarms.
Equipment Setup
- Place the smoke blower on a stable, level surface and attach the hose to the blower.
Connect the hose to the plumbing (Figure 2)
Cleanouts: Detach the 4-in-1 Cleanout Adapter from the hose elbow. Screw the adapter into the cleanout (Teflon tape can be used to prevent leaks). Connect hose elbow to adapter.
For other connections, a rag or even tape can be used as needed to achieve a good seal.
Verify the blower is turned OFF and plug in blower
Figure 2
(optional) Position assistant(s) inside the building.
Important! - Verify Unrestricted Airflow: Turn on the blower WITHOUT initiating any smoke. Verify that air is flowing freely. You should be able to feel the air being drawn into the blower intake. If the system is not flowing air, there is a restriction in the system which must be cleared before doing a smoke test. Smoke testing a restricted system will be ineffective and will create heavy smoke blow-back at the blower. Note that a restriction in the plumbing may itself be the defect you are attempting to locate.
A Properly Setup Smoke Blower
Performing the Smoke Test
Note: A good rule of thumb is to use the least amount of smoke necessary to accomplish the task. While F Series blowers can be run indefinitely, there is rarely a reason to run it for more than a few minutes. “Over smoking” a system can result in excessive smoke accumulation in unintended areas. Smoke is used only as a visual indicator of plumbing defects and is not intended for inhalation. Brief incidental exposure is acceptable, but do not enter a space with excessive smoke accumulation.
initiate Smoke
Observe roof vents. Within a few seconds, smoke should be emitting from all roof vents– this indicates a proper test. Lack of smoke may indicate a blockage or smoke flowing in an unintended direction.
Inspect the building plumbing. The presence of visible smoke confirms a defect. Once defect is located, turn the Smoke Blower OFF.
Ventilate the building as needed before reoccupation. Smoke used for plumbing smoke testing is non-toxic when used as directed.
Stow Equipment
Wipe down blower housing before storage. Store blower and consumables cool and dry.
