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Smell test method (C) Daniel FriedmanHow to Usa an Odor Event Log
Use this Odor Localization Event Log to Find Building Odor Sources

Building Odor localization log: use this odor-event log to help determine the source of building odors.

Using a log to record observations of odors related to time of day, weather, equipment operation, building occupancy and activities can help determine where building odors originate: a process of odor localization.

In this article series we provide a series of detailed articles on finding the source of and stopping unwanted building odors in buildings.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Odor Localization Log Tracks Sound-Sources & Events

Skunk animals in a home © D Friedman at InspectApedia.com Watch out: some odors in and around buildings can be immediately dangerous, such as LP or natural gas leaks and some sewer gas leaks, while other sewer odors, even if not at an explosive level, may indicate viral and bacterial hazards.

How to Find the Source of Building Odors by Keeping an Event Log

Table 5-14 is shown at the top of this page.

Two general approaches to tracking down the source of Odors in buildings

  1. Where is Odor strongest?

    Using people with an acute sense of smell or using our smell-patch test kit can often pinpoint an odor source.

    See SMELL PATCH TEST to FIND ODOR SOURCE
  2. What conditions seem to correlate with odor production:

    Keep a log of factors that can help identify Odor source such as

For unidentified odor sources, general advice on tracking down the source and cause of annoying can sometimes be resolved quickly using

our ODOR DIAGNOSIS CHECKLIST, PROCEDURE.

To track a mystery-Odor or sound to its source, try keeping a odor log like the one we provide here, noting the following items - (print and use the table below if you find that helpful):

You can print this web page directly, or save it to a PDF file, or if you prefer, print this

ODOR EVENT LOG & CHECKLIST FORM [PDF] printer-friendly PDF - we recommend that you PRINT THIS FILE to record odor observations such as time of day, weather, temperature, sunlight, & possible sources as an aid in finding the actual source of odors & smells in or around buildings


InspectApedia.com Odor Event Log
Used to Track a Building Odor to Its Cause or Source©

[Print this Page for use as a sound event diagnostic log]
Date & Time Observation Comments

Odor Observed: dates, times, description

   The date and time of the Odor at each occurrence, especially when it was first observed
Odor Observers:  

Who smells the Odor? People's smell sensitivity or ability varies widely; use someone with acute sense of smell to help track down Odors;

don't rule out medical conditions that can cause people to perceive Odors that are neurological or bodily in origin
Building activities:  

Activities: who is present in the building, people, animals; walking or moving around, using equipment, using plumbing, etc.

For sewer gas odors, what plumbing equipment has been in use, when?
Apparent Odor location  

Probable Odor origin by location:

Differences in odor perception between what is observed indoors, at different indoor locations, and outside.

Where is the Odor strongest?
Odor properties or type: describe the Odor   Odor properties:
  • Odor occurrence correlated with any of the items in our Odor checklist
  • Odor type: can you characterize the odor among common odor sources such as

    bathroom odors

    chemical odors

    food odors

    gas or gas leak odors

    animal odors

    water odors

Some common odor problems such as gas odors and sewer smells are addressed by specific articles in this series.

Building Mechanical Equipment:

air conditioner, heat, fans, water pump, water softener, appliances, cooking equipment, fans, plumbing fixtures, etc. in-use, on or off at time odor was observed

Elevator use as well as opening and closing of windows, doors, and stairwell doors affect odor transport between building areas

  

What equipment is operating or turned off in the building;

Mechanical equipment such as elevators, fans, exhaust systems, pumps, heating or cooling equipment, or appliances may be making an odor

Or heating or cooling equipment can cause temperature changes that affect odor transport from one building area to another

Or fans and ductwork may move odor from one place to another in a building
Weather conditions & odors   What weather conditions might be pertinent such as wind, wind direction, temperature, temperature changes or shifts, rain, or freezing conditions
Site & neighbors & odors   Site activities: are there possible odor sources outdoors but near the building from neighboring buildings, power transformers, neighboring businesses, equipment, etc.
Sunlight & odors   Sun direction and sunlight levels - sunlight can correlate with thermal expansion of or off-gassing of materials and thus odors
Odor Observation Time  

Time of odors: when did the smell first appear in or around the building?

What changes occurred at or shortly before that time in building occupancy, use, modification, etc.

What mechanical equipment is or was in operation?
Temperatures & odors   By noting temperatures and temperature changes we might trace odors to off-gassing sources or to the operation of heating or cooling systems
Wind:   

Wind conditions: is wind blowing? From what direction, at what strength;

does wind correlate with Odor occurrence?
Building modifications, changes:   What has changed in the building that might be relevant such as installation or removal of equipment
Additional Odor Observations:    
     
     
Notes: 

Also see these odor source tracking forms

 


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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: track down source of mystery odor that gets better when the garage door is open

Re-posting from private email:

You have a very helpful website...thank you for the great resources. We have a mystery smell that has been coming through our hvac vents for the last 5 months that just appeared after living in the house for 4 years. That is driving us crazy.

The Smell is a musty smell with a hint of cigarette/burning smell, but we don’t smoke, nor do any of our neighbors.

Unfortunately I can’t find anyone on google that describes a similar smell. We have had multiple experts out and are $5,500 into this process with no solution. Hoping you have dealt with this before and can give some ideas to explore.

What we have done so far: professionally inspected/cleaned the vents, had mold air test samplings throughout house, had multiple hvac companies inspect the furnace and ac units and no obvious issues. One of the hvac companies was convinced that the smell was coming from the crawl space and being pulled into the supply vents because they are running through crawl space and we’re not sealed well by the builder.

The theory was that we had negative pressure in the house because the furnace didn’t have outside air. So they sealed all the ducts, replaced some old insulation around the return ducts, ducted out the returns to grills (previously just between floor joists), sealed the furnace better, and added an outside air duct on a timer to bring fresh air into the return ducting.

After all the improvements, the smell might be slightly better but is still present. The smell moves around the house and the strength changes by the hour, but is most obvious in two rooms, and in the morning and night. For the first two months it could only be smelled in the vents in 2 rooms, but can now be smelled in numerous vents throughout the house. Vents only smell when hvac furnace/ac or fan are running. The strongest smell is right next to the furnace ( newer 80% efficient gas furnace with ac).

The furnace is located in the garage. Through much trial and error, we discovered that if we left the garage doors open to outside all day, the smell goes away even if the hvac equipment is running.

This makes me think it is one of two things: (1) there is a smell in the garage that is being sucked into furnace, or (b) there is an issue with furnace and the smell somehow dissipates when the furnace has access to large amounts of fresh air (i.e. when garage doors are open).

There is lawn equipment and other items stored in the garage (always have been) but the smells from the those items are mild and don’t smell anything like the mystery smell. One interesting note is that when we pull a car into the garage after being shut for a while the car will immediately bring in the smell into the cars vents.

That said, the garage only really smells around the furnace area of the garage.

Any ideas would be much appreciated- we are running out of ideas and costs are building up. - Anonymous by private email 2020/10/18

Moderator reply:

Well thanks for a heck of a challenging question.
Let's start by saying I have no idea, no confident diagnosis, and cannot from mere text or even text and reports and photos. Your onsite people surely are smarter than I and can see a lot more.

All that arm-waving and ducking done,

Your own analysis says you've done some great detective work.

Let's investigate

What's happening when the garage door is open or shut.

Opening the garage doors, moreso where the garage is where your heating system is located, has these effects, (plus others that you or another astute onsite investigator might discover):

Some odor diagnosis questions & suggestions:

For a more-orderly and complete approach to odor diagnosis than my off the cuff reply

We'll continue from here when I hear more from you.

Question: what instrument can I use to track a Odor to its source ? A mechanic's stethoscope is too limited

Is there an instrument available that could be used to locate sound source?

Reply: six approaches used by acoustical engineers to pinpoint or localize Odor and sound sources

I agree that a combustible gas analyzer or gas detector can be useful but only in tracking down sewer gases, methane, LP gas or natural gas leaks.

See details at GAS DETECTION INSTRUMENTS

For moving from an ambient widespread Odor to a source requires a combination of careful smell testing by a sensitive observer along with methodological investigation such as keeping a Odor-event log to relate sounds to changing conditions of time, weather, equipment in or out of operation, nearby activities, combined as well with visual inspection and occupant interviews.


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Continue reading at ODOR DIAGNOSIS CHECKLIST, PROCEDURE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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ODOR EVENT / SOURCE LOCALIZATION LOG at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING NOISE DIAGNOSIS

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