FHB Logo Facebook LinkedIn Email Pinterest Twitter Instagram Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe

In every issue you'll find...

  • Expert insights on techniques and principles
  • Unbiased tool reviews
  • Step-by-step details to master the job
  • Field-tested advice and know-how
Subscribe Now!
Subscribe
  • How-To
  • Design
  • Tools & Materials
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
  • Join
  • Log In
Subscribe

Discussion Forum

Discussion Forum

Asbestos and HVAC installation?

tinybluebungalow | Posted in Energy, Heating & Insulation on January 26, 2021 11:05am

Husband and I live in a 100-year-old bungalow with Zonolite vermiculite insulation — likely to contain asbestos — in the attic. We’re having it professionally remediated, in part so that the attic can become a usable space and we can install much-needed central AC. This morning, the asbestos contractor told me that, though they would guarantee removal of all asbestos in attic, it’s possible that we might have some in our walls — trickled down from the attic over the years — which they wouldn’t be able to access and remove.

My question is: if there’s asbestos in the walls, and we have ductwork installed, are we creating a situation where we’re just blowing asbestos into our house? Or, so long as everything is sealed up properly, post installation, will it be okay? Is this just pointlessly opening up a huge can of worms, and we should stick with window units?

Reply

Replies

  1. User avater
    UncleMike42 | Jan 26, 2021 02:46pm | #1

    You should be able to have the HVAC installed without disturbing the walls. You likely can have all the ductwork installed in what is now the attic. What kind of heat is in the bungalow?

    In general, asbestos that is sealed up is not a hazard. A good idea to seal up any penetrations, such as plumbing, electric switches and outlets.

    1. tinybluebungalow | Jan 26, 2021 03:27pm | #2

      Thanks for your reply. It's all radiator heat now, so no existing ductwork. And, it's a two story bungalow -- so while ductwork for the second floor will remain in the attic, to reach the first floor, something is going to have to come down the walls.

  2. Norman | Jan 26, 2021 04:52pm | #3

    Not necessarily. Look into SpacePak & mini split type systems.

    Good luck.

  3. User avater
    UncleMike42 | Jan 26, 2021 07:50pm | #4

    If you are concerned about asbestos in the walls, make sure to be up front with your HVAC installer. You probably will have to have the mitigation folks make a follow-up visit.

  4. Sm_raudales | Jan 28, 2021 08:27pm | #5

    Asbestos within Air Conditioning and HVAC.
    https://www.newcentralairconditioner.com/

    Air conditioning systems and ductwork within buildings can contain asbestos whereby exposure to friable and respirable fibres may occur unknowingly. This may occur for many years until it may be found due to significant disturbance by HVAC or air conditioning tradesman through upgrades and refurbishments. The first tell-tale sign may be white dust which may contain visible fibres one morning when first arriving at work. Other times, the hidden asbestos may not be found until an asbestos assessor has identified that there may be potential for asbestos to be contained within the HVAC air conditioning system.

    Where might the asbestos in the HVAC air conditioning system reside?
    Asbestos was used widely for the thermal resistance properties which was a primary use and concern in HVAC air conditioning systems, particularly in the insulation surrounding the reheating banks or coils throughout the ductwork. During the winter as warm air is being distributed throughout the building, it will cool down; to prevent this, re-heating bars or coils similar to an old electric bar heater are located throughout to re heat the air and reduce the thermal inefficiency of the system It is within these sections of reheating bars, that may contain a low density asbestos material called millboard.

    The millboard material surrounding the heating banks will over time start to deteriorate and release and liberate the material, including the asbestos fibres into the air stream. This may then expose people over time whilst they are occupying the building. Identification of asbestos within the ductwork can be done by a visual inspection of the heater banks and a sample of the material sent to a NATA accredited lab for asbestos testing. Sampling of the duct through scarping up the dust under controlled procedures by an asbestos assessor or using tape samples is most appropriate, depending on the amount of dust present that may be able to be sampled.

    This detection limit for asbestos concentration is some 10 times less than the exposure standard for asbestos, and the low level exposure is generally not a major health hazard until there is significant disturbance.

    Significant disturbance of the asbestos in the air conditioning system may result from cleaning of the ductwork or HAVC & air conditioning tradesman cutting into the ductwork that contains the asbestos mill board material. This potential exposure is a concern not only for the people within the building, but more so the HVAC and air conditioning tradesman who may themselves be subject to asbestos exposure on a daily basis.

    The most common form of asbestos identified within millboard surrounding the heater banks is chrysotile asbestos commonly known as white asbestos. Amosite asbestos has also been found, more commonly where there has been a sprayed applied limpet asbestos within air conditioning plenums and ceiling voids where the asbestos is transported through at velocity.

    What precautions should be taken?
    Firstly both an asbestos inspection of the building should be undertaken with the asbestos register present and available for all people within a building and those tradesman including HVAC and air conditioning consultants being able to have access to this information. If there is not any information relating to the potential for asbestos within the air conditioning system then an inspection of the heater banks and ductwork including dust and insulation samples be undertaken.

    In many instances dust within the ducts can contain asbestos, particularly at the elbow joints where the particles impact against the ducting and fall down due to the inadequate transport velocity at the sharp bends in the duct work.

    Where asbestos is found within the building, an asbestos management plan should outline emergency procedures, what to do and who to contact, along with a risk assessment, asbestos air monitoring plan and asbestos sampling procedures.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Industry-First Cordless Rebar Cutter and Bender

A brushless motor and 36v batteries power Metabo HPT’s cordless rebar bender and cutter.

Featured Video

Video: Build a Fireplace, Brick by Brick

Get an overview of the process of creating a traditional-style fireplace that burns well and meets current building codes from experienced mason Mike Mehaffey.

Related Stories

  • Podcast 484: PRO TALK With Color Consultant Paula Gaull
  • Using Liquid Flash at a Wall-to-Foundation Connection
  • Forming Foundation Walls
  • Track Lighting for Functional Ambiance in Busy Spaces

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

BOOKS, DVDs, & MERCH

Shop the Store
  • Code Check Building 4th Edition
    Buy Now
  • Pretty Good House
    Buy Now
  • Outdoor Projects
    Buy Now
  • 2021 Fine Homebuilding Archive
    Buy Now
  • Shop the Store

Fine Homebuilding Magazine

  • Issue 309 - Aug/Sept
    • 10 Steps to Install Crown Molding on Cabinets
    • How to Get Sturdy Walls Without OSB
    • Choosing the Right Construction Tape for the Job
  • Issue 308 - July 2022
    • Pretty Good House Book Excerpt: Copper Farmhouse
    • 10 Dos and Don'ts for Electric In-Floor Heat
    • A Sturdy Rail for Outdoor Stairs
  • Issue 307 - June 2022
    • How to Raise a Post-Frame Home
    • Trimming Deck Stairs
    • Evolving an Energy-Efficient Envelope
  • Issue 306 - April/May 2022
    • Framing Stairs to an Out-of-Level Landing
    • Building a Zero-Energy Home for Less
    • Good-Looking and Long-Lasting Traditional Gutters
  • Issue 305 - Feb/March 2022
    • The Steady Surge in Residential Solar
    • The Fine Homebuilding Interview: William B. Rose
    • How Good Is Your Air Barrier?

Fine Homebuilding

Follow

  • twitter
  • facebook
  • instagram
  • pinterest

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences

Taunton Network

  • Green Building Advisor
  • Fine Woodworking
  • Fine Gardening
  • Threads
  • About
  • Contact
  • Advertise
  • Careers
  • Copyright
  • Terms of Use
  • Site Map
  • Do not sell my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2022 The Taunton Press, Inc. All rights reserved.

X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Account

  • Log In
  • Join

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Shop the Store

  • Books
  • DVDs
  • Taunton Workshops

More

  • FHB Ambassadors
  • Reader Projects
  • Podcast
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • twitter
  • facebook
  • instagram
  • pinterest

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in