Smoke Fluid vs Smoke Candles for Sewer Testing

Superior Signal; The industry experts!  Superior Signal is the innovator of the Smoke Testing Technique for inflow studies.  We’ve enjoyed an excellent reputation of producing quality smoke testing products at affordable prices for over 60 years.  We supply smoke and blowers to meet any smoke testing specification; classic smoke candles, or sewer smoke fluid.  Whatever your choice, you can be sure you’ll receive only the best products and support that comes with our many years of experience.  Our products and specifications meet all recommendations of NASSCO, EPA, & WEF, and have identified leaks in millions of feet of sewer line in thousands of municipalities.

Classic Smoke Candles -vs- Smoke Fluid

Smoke Candles and Smoke Fluid are the two most effective methods of generating smoke for mainline sewer testing. While both methods will get the job done, each has it's advantages, often leading crews to favor one method over the other. So which is right for you? Lets start by understanding how each method works.

Smoke Candles are compact, biodegradable smoke generators that when lit, produce a dense white smoke. (The visible portion of this smoke is actually atmospheric moisture and not a true "smoke" like that from a fire). The "smoke" emitted from the candle is typically drawn into a manhole blower's intake and blown into a manhole.

Smoke Fluid is a petroleum-based oil that is typically injected into the exhaust stream of a blower's gasoline powered engine. The fluid is heated from the exhaust and converted to smoke where it is then injected into a manhole blower's intake and blown into a manhole.


So what are the advantages of each method?

Advantages of Smoke Candles:

  • DSuperior 3C Smoke Candleensity:  Smoke candles produce a notably denser smoke than that produced by smoke fluid. Dense smoke is more visible and therefore more effective at revealing faults.  Some operators find they can get the job done faster, and find more faults with Smoke Candles.
  • Less Expensive Equipment:  Smoke Blowers designed to be used exclusively with smoke candles are simpler and less expensive than fluid blowers. However, some fluid blowers, such as those offered by Superior Signal, have the ability to use both smoke fluid AND smoke candles.
  • Simplicity: Smoke Candles consistently produce dense smoke in all conditions with no adjustment required as compared to smoke fluid which must be brought to a proper temperature and flow rate to make smoke efficiently.
  • Pace:  Smoke Candles generate smoke for about 3 minutes.  This keeps the crew moving quickly through the test area, which can help maintain the pace of the project, and avoid labor cost overruns.  Double-wick candles can easily be daisy-chained together to produce 6, 9, or 12 minutes of smoke – as needed for the particular test situation.

Advantages of Smoke Fluid:

  • Superior SL Smoke FluidMore Convenient to Use:  Smoke fluid is convenient to use because once you have the Smoke Blower set properly the system will keep smoking for a long period of time with no intervention.  A smoke fluid system can smoke for hours with just occasional pumping of the fluid tank.  Some operators prefer this convenience.
  • Lower Cost Per Minute:  Smoke fluid is less expensive to run per minute of smoke, although the smoke is typically less dense.  Some operators find this works just fine, and can save money on a project.
  • Less Odor:  Smoke from fluid can have less odor than smoke from candles – which has a pungent smell like burning paper.  Smoke fluid from Superior Signal produces virtually no odor at all.
  • Storage & Shelf Life:  Smoke fluid can be stored anywhere almost indefinitely, whereas smoke candles must be stored cool and dry, and have a typical shelf life of 1 to 2 years.


Fluid System -vs- Fluid System;

Superior Smoke Fluid

  • Offers equal or better results than other fluids and is more favorably priced.  It is also as safe and clean as it gets!
  • Superior Smoke Fluid Systems do not simply tap into the existing muffler.  Our heating chamber is custom made to maximize efficiency.  It is larger than competitive systems to retain heat and allow more time to convert fluid to smoke.
  • The heating chamber is also insulated to maintain the optimum temperature range to produce dryer smoke for longer durations.
  • Our precision injector and valving system were designed to properly regulate fluid flow and further reduce the chance of wet smoke. 

Competitor’s fluid systems

  • Fluid is injected into the engine’s existing muffler, which obviously was not designed by the engine manufacturer with the idea of making smoke.
  • Muffler is not insulated.


Toxicity in Perspective

Other manufacturers typically only offer one type of smoke product, therefore it makes sense that their sales pitch would be one sided.  We welcome fair competition, however it appears that one supplier finds his only recourse against our fine reputation to be a negative campaign using misleading statements, and scare tactics rather than product performance.

Superior Signal offers both smoke candles and fluid systems.  When considering the potential danger of ANY smoke, you must consider the level of exposure an individual would have.  One competitor has cautioned about exposure to “dangerous” Zinc Chloride type smoke, and warns you to wear your respirator if the possibility of exceeding the OSHA permissible exposure level (PEL) exists.  Truth is, you should wear a respirator if you exceed OSHA PEL of ANY smoke, including the competitors liquid smoke!

While competitors claim liquid smoke to be 100% safe and 100% clean.  It should be noted that this is their interpretation of tests that were done by a lab they hired.  This lab does not offer an opinion on the results of the testing, nor do they specifiy which smoke fluid was tested.  Over the past few years the competition has offered at least two different fluids.  One is Chemical Abstract System (CAS) #64742-30-9 Mineral Seal Oil, the other is CAS# 64742-46-7 a petroleum distillate.

Remember that all liquid smoke systems use the blower engine exhaust to heat and propel the smoke.  Is this exhaust mixture toxic? Again, it depends on exposure levels.  All smokes can be used safely, but does it sound 100% safe to you? 


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