Burying Attic Ductwork Covered With Asbestos Paper Wrap With Insulation?

NOTE: If Your DFW Home Was Built In 1980 Or Later 

Click Here To Read Part-1 Of This Article: Bury Attic Ductwork In DFW-Part 1

This article is Part-2 of Our 2-Park Article About Burying Attic Ductwork, that’s covered with Asbestos Paper Wrap in attic insulation.

Part-2 Is Written Only For Owners Of DFW Homes — Built Before 1980.

What You Will Likely Find In The Attic Of A Pre-1980 DFW Home

DFW Homes With Orginal, Metal Ductwork — Likely Have Asbestos Paper Wrap On The Outside.

The Product Show Below Is R-8 + A Vapor Barrier.  There are other brands available too.

Image Source: Amazon.com Embedded Link

Shown: US Energy Products R-8 Insulation + Vapor-Barrier + Radiant-Heat Barrier. 

Click On Image To; View Product, Read Details, or Purchase From Amazon.com

NOTE: This Product Has A Foam-Core Between Two Outer Foil Layers.   It’s Not: “Bubble Wrap”.

The Manufacture’s Website Says:

• • 1/4″ (5 MM) thick.
  • A layer of Closed-Cell Foam — is bonded between 1 layer of highly-reflective, metalized-aluminum, polyester film — on each side.
  • Reflects 97% of radiant heat.  Rejects the sun’s heat inside the attic — during summer.
  • Emits less than 3% of heat from ducts during winter.
  • Not affected by moisture or humidity.
  • Inhibits condensation.
  • Does not promote the growth of; fungi, mold, or mildew.

• • Hold it in place with; staple, nail, glue, or spray-adhesive.
  • Does not compress, collapse or disintegrate.
  • Class 1 / Class A Fire-Rated radiant barrier that has passed the ASTM E84 test & ASTM E259.

Source: https://www.usenergyproducts.com/products/R-8-hvac-duct-wrap-insulation-reflective-2-sided-foam-core-4-x-125-500-sq-ft

NOTES:

• This product can be used to cover uninsulated metal ductwork.
• All 4 sides must be covered.

A Scientific Study Was Performed By Home Innovation Labs

To Test If Ductwork (Buried In Attic Insulation) Would Sweat

Location: South Carolina’s Warm & Humid Climate (similar to DFW’s)

The Question: When Ductwork Is Buried In Attic Insulation — Is There Potential For Condensation To Form On Its Exterior

In Humid Climates (like DFW’s) During The Cooling Season?

Ductwork Definitions:

• Furnace Plenum: It’s the begging of the ductwork — and is attached to the furnace.
• Note: The Ductwork’s Trunk Line Attaches (to the other end) of the Plenum.

Image Source: CanStockPhoto

Shown: Furnace Plenum (behind the vertical white pipe & diagonal black pipe).

• Trunk Line: (starts at the plenum): It’s a larger duct that supplies air to the smaller Branch Lines.
• Branch Line: (starts at the trunk line) — Branch(es) Serve Each Room.
• Boot: (c0mes through the ceiling — and connects the Branch line (in the attic) TO The Register (inside the house).

Image Source: Shutterstock

SHOWN: Trunk Line: The largest of the round pipes visible.

SHOWN: Branch Line: The smaller of the round pipes visible.

SHOWN: Boot:  The Rectangular Piece — connected to the branch line.

• Register: What you can open & close.

Image Source: Shutterstock

SHOWN: Register

Copy The Link Below Into Your Browser To Read The Original Home Innovation Labs’ Report.

https://www1.eere.energy.gov/buildings/publications/pdfs/building_america/compact-buried-ducts-hot-humid.pdf

Page 47 of 61: Shows The Attic Ductwork During The Home’s Construction

NOTE: Photos Below Are Representative Of What The South Carolina Home’s Attic Ductwork Looked Like.  Photos are of another home studied.

• Figure 15: Shows The “Trunk” Line (definition above) — Was Encapsulated In Spray Foam (because it’s too large to bury in insulation).
• Figure 15: ALSO Shows The (gray) “Branch” Lines (definition above).  They are compact, flexible ductwork with no modifications.
• Figure 16:  Shows The Attic After The “Branch” Lines Were Buried In (blown, fiberglass) Attic Insulation.

The Study’s Goals

1. Develop criteria for ductwork (buried in attic insulation) that:

• Uses common building materials.
• Does not require ductwork to be encapsulated (surrounded) with spray foam — to prevent condensation.

2. Establish criteria to bury (compact, flexible ductwork) — to reduce energy losses (caused by ductwork being hung above attic insulation).

3. Develop guidance to help determine the reduced heating & cooling needs — due to compact ductwork buried in attic insulation.

The Subject Home is located in Lady’s Island, South Carolina.

Lady’s Island is roughly halfway between Savannah, GA & Charleston, SC.   It’s quite near the ocean, which explains the quite high Dew Point.

Test performed during August.  Typical Dewpoint: Near 80 degrees (+9 over DFW)

The Study’s Findings

NOTE: 37 Sensors Monitored; Temperature, Relative Humidity, & Dew Point At These Locations;

• Outdoors
• Inside The Attic
• Inside The Living Space – at the ceiling.

• Outdoor Temperature approached 95°F.
• Outdoor Dew Point approached 80°F.

• Attic temperature peaked near 120°F.
• Attic Temperature Sensors (spaced at 3.5″, 6″, & 8.5″ above the attic floor) — varied by up to 15°F (daytime) and 3-5°F (nightime)

Dew Point Was Measured:

• Outdoors
• Inside the attic (above the attic insulation).
• Within (inside) the attic insulation.
• At a Supply-Air Duct Boot (connects air coming from the Branch Line to the register vent inside the house) located near a ceiling.

• A/C produced cooled air at 55°F

(Compared DFW’s August Weather)

• Average High Temperature = 97.5F.
• Average Dew Point = 71°F.
• DFW attic temperature can reach 140°F+ on a 95°F day.  Attic temperature is higher during full sunshine AND lower during full clouds.

• Properly operating Central A/C produces air that’s up to –20°F — lower than the thermostat’s setting.

Source: https://www.wunderground.com/history/daily/us/tx/dallas/KDAL/date/2021-8-15

Source: https://www.radiantguard-psg.com/live-attic-temperatures-frisco-tx/

The Study’s Conclusions

• Outdoor Dew Point approached 80°F.
• Dew Point (inside the attic, above the insulation) = 68°F — 80°F during most of the day.

• Dew Point (at the register — in the room’s ceiling & under the insulation) = 58°F To 68°F.
• Dew Point at the register was –10°F To -12°F lower than above the insulation.
• Dew Point within (inside) the attic insulation was notably lower than the attic’s dew point (above the insulation).

• No condensation was measured nor observed along the ducts.
• Near the ducts (buried inside attic insulation) — there was No strong risk of condensation.

NOTE: This Research Study’s Conclusions (plus another source shown just below) Counters Common Opinions That Attic Insulation Doesn’t Lower Humidity.  

Another Source:

• High-quality insulation offers enhanced humidity control.  Insulation is able to help keep moisture out of your home.
• With the vapor-retarder ability of insulation materials — the amount of moisture able to transfer into your home is reduced.

Source: https://www.homelogic.co.uk/does-insulation-help-with-humidity-the-definitive-answer

Copy The Link Below Into Your Browser To Read The Entire Report — That We Summarized Above.

https://www1.eere.energy.gov/buildings/publications/pdfs/building_america/compact-buried-ducts-hot-humid.pdf

(Conclusions Begin On Page 30)

By The Early To Mid 1980s — Most HVAC Contractors Started Using Flexible Ductwork (flex-duct) In Attics. 

Flex-Duct is used as a cost-cutting measure.  Both flex-duct material and its installation costs are notably lower.

• Before The Early 1980s — DFW homes typically had metal ductwork.
• Note: It’s possible metal ductwork was removed and replaced with flex-duct.
• There’s typically a combination of round and rectangular metal ductwork.
• Metal ductwork may, or may not, have exterior insulation.

Here’s An Example Of An Asbestos Encapsulating Product

It’s Made Of Fiberglass — And Wraps Around The (asbestos covered) Surface. 

Rewettable Fiberglass Pipe Lagging/Wrap

• It’s a canvas-like product made of fiberglass woven thread and embedded with an inorganic, rewettable coating.
• While wet, the coating is much like a plaster-like paste — that hardens into a cast barrier once fully dry (similar to a cast for a broken bone).
• Once installed over asbestos — asbestos fibers are covered and contained.

Source: https://www.buyinsulationproductstore.com/blog/how-to-encapsulate-asbestos-pipe-with-rewettable-lagging-cloth/

NOTE: Al’s Plumbing, Heating, & A/C Does Does Not Sell Or Install Asbestos-Containment Products.

NOTE: Al’s Plumbing, Heating, & A/C Does Not Endorse Any Specific Asbestos-Containment Product Only Because We Don’t Have First-Hand Knowledge Of Them.

Asbestos-Containing Products Showing NOTABLE Signs Of; Damage, Deterioration, or Having Been Disturbed

Are Likely Releasing Asbestos Fibers — And Posing A Potential, Major Health Risk.

Copy The Link Below Into Your Browser To See Many Photos Of Damaged/Deteriorating Asbestos Paper Wrap:

Click on the right arrow to see more photos)

https://www.flickr.com/photos/asbestos_pix/3426980199

In This Case — 1 Of These 2 Actions Should Be Performed By A Professional:

Asbestos Was Used In Homes As A Vapor-Retarder In Several Locations:

• Asbestos Paper Wrap — applied to HVAC Ductwork (to seal lakes and as a vapor-retarder).
• Asbestos Paper Wrap insulating ability is negligible.

Common Locations Asbestos Was Used As A Vapor-Retarder:

• Behind brick veneer.
• Behind plaster walls.
• Under linoleum flooring.
• and others

Asbestos helped these products (plus others)

Perm Rating Definitions:

A Perm Rating: Indicates How Much Humidity Can Pass Through A Material.

• The lower the Perm Rating — the less moisture can pass through it.
• A Vapor-Barrier prevents humidity from passing through it.
• A Vapor-Retarder slows humidity passing through it.

PERM Rating:

• <.1               Class I—-  Impermeable                   Example:      Polyethelene (plastic) sheeting.  Perm: 0.1 — 1.0
• .1 0 – 1.       Class II — Low Permeability           Examples:    Paper-faced fiberglass batt insulation.  Perm:1.0
• .1-10.0     Class III — Permeable                 Examples: Blown Fiberglass insulation & Unfaced, Batt, Fiberglass Insulation. We could not find Perm Ratings for blown or batt.
• > 10.          Class IV — Highly Permeable           Example:      Drywall: Perm 50.

Source: https://www.aepspan.com/high-permeability-underlayment-blog/

• Blown Fiberglass Insulations Perm Classification: Class III-Permeable.   
• This classification shows that blown fiberglass insulation has some, limited vapor-retarding ability.
• This Explains The Study’s Findings — that DewPoint within (inside) the attic insulation was notably lower than (above) the insulation.

Source: https://www.buildinggreen.com/sites/default/files/BG_Insulation_Recommendations.pdf

Source: https://insulationinstitute.org/im-a-building-or-facility-professional/commercial/installation-guidance/managing-moisture-in-commercial-construction/vapor-retarders/

Sources: 

• (Report): U.S. Department of Energy Building America Program
• (Study Performed By): Home Innovation Research Labs
• (url) https://www1.eere.energy.gov/buildings/publications/pdfs/building_america/compact-buried-ducts-hot-humid.pdf    PAGE 16

Older DFW Home’s Ductwork Wasn’t Sealed

OR Sealed With Products That Failed In A Short Time

Image Source: Shutterstock

Shown: Uninsulated Metal Ductwork

According To The EPA ENERGY STAR® Program:

• Duct leakage should be less than 5% in a newly installed HVAC System.
• The typical home leaks 20% of cooled/heated air.
• In older homes, it is not uncommon for duct leakage to be 30%-50%.

• In older DFW homes, ductwork sealing products did not hold up to summer attic temps (up to 160 degrees).
• Early sealing products (like duck tape) — failed in as little as a few days.
• In A Houston, TX Study: The cost to seal ductwork (for a 1,650 square foot home) — ranged from $575-$2,675.
• In that study — sealing ductwork reduced annual cooling/heating costs by $200-$400 per year.

• The Duct-Sealing price range depends on the type of sealing performed.
• Sealing can be done inside the ductwork (details below) OR outside the ductwork — with mastic.
• Cost is much lower with inside ductwork sealing.

Source: U.S. Dept. Of Energy  https://www.nrel.gov/docs/fy12osti/53494.pdf

Exterior Ductwork Sealing Can Be Done Inside The Attic — But There’s A Simpler & Less Expensive Solution. 

Airborne (inside) HVAC Duct Sealant

Image Source: YouTube Embedded Video

Shown: A Demonstration Of Aeroseal Duct Sealing System.

NOTE: Al’s does not endorse any specific ductwork-sealing system — only because we don’t have first-hand knowledge of every system.

A Google search will provide contractors in your area.

Here’s How Airborne (inside) Ductwork Sealing Works

• First, the ductwork must be cleaned.

Click Here To See A Before & After Ductwork Cleaning Photo: Before & After Ductwork Cleaning

Next:

• Plastic is placed over air-vent grilles (where air comes into rooms), and registers (where air returns to the furnace).
• An airborne polymer mixture is injected into the ductwork — under high air pressure.
• This polymer remains airborne — until it encounters a leak.
• At leaks, the polymer’s particles get pushed into the leaks.
• The particles stick together and seal the leak.

Note: Al’s Plumbing, Heating, & A/C Doesn’t Endorse Any Specific Ductwork Sealing Process Or Contractor Only Because We Don’t Have First-Hand Knowledge Of Them.

On A Side Note

Many Concrete-Asbestos Products Were Sold Under The: “Transite” Brand Name. 

Transite Branded Products Were Made By Johns Manville Corp.

• Concrete-Asbestos Transite (shake-style) exterior siding

Image Source: Shutterstock

SHOWN: Asbestos-Cement Exterior Siding

• Transite Roof shingles.
• Transite HVAC Ductwork (under slab)

Click Here To See Transite (brand) HVAC Concrete-Asbestos Ductwork: Transite (brand) HVAC Ductwork

• Attic Insulation sold under the: “Zonolite” Brand Name.  Zenolite was made by W.R. Grace & Company.\

Click Here To See Zonolite (brand) Attic Insulation: Zenolite Attic Insulation

Asbestos Was Added To Several Home Decor Products

• Sheet Linoleum (on the back side — as a vapor-retarder)
• 12″x 12″ Linoleum floor tiles

Image Source: Shutterstock

SHOWN: Vinyl-Asbestos (VAT) Floor Tile

• Ceiling Tiles

Click Here To (one version of) Asbestos Ceiling Tiles: Asbestos Ceiling Tiles

• Ceiling (popcorn) texture
• Textured paint
• Artificial ashes & embers for gas fireplaces
• and others

Source: http://www.iatp.org.uk/wp-content/uploads/Appendix-3-17-Work-with-Asbestos-Paper.pdf

Source: https://www.pnwig.com/blog-category/asbestos/blogs?blog_id=building-materials-containing-asbestos

There Are Over 3,000 Home Building-Products That May Contain Asbestos

■Acoustical ceiling texture (“popcorn”)                             ■Gray roofing paint
■Asphalt flooring                                                                    ■High-temperature gaskets
■Base flashing                                                                         ■HVAC duct insulation
■Blown-in insulation backing                                              ■Incandescent light fixture
■Boiler/tank insulation                                                         ■Joint compound/wallboard
■Breaching insulation                                                           ■Laboratory hoods/table tops
■Brick mortar                                                                         ■Laboratory fume hood
■Built-up roofing insulation                                               ■Mudded pipe elbow
■Caulking/putties                                                                 ■Nicolet (white) roofing paper
■Ceiling tiles/panels/mastic                                              ■Packing materials
■Cement board/Brand: Transite                                       ■Paper fire box in walls
■Cement pipes insulation                                                   ■Paper on backside of fiberglass insulation
■Cement roofing shingles                                                  ■Pipe insulation/fittings
■Chalkboards                                                                       ■Plaster/wall joints
■Construction mastics                                                       ■Poured flooring
■Duct tape/paper                                                                ■Rolled roofing
■Ductwork flexible connections                                      ■Roofing shingles
■Electrical cloth                                                                  ■Sink insulation
■Electrical panel partitions                                              ■Spray-applied insulation
■Electrical wiring insulation                                           ■Stucco
■Elevator brake shoes                                                       ■Sub flooring slip sheet
■Erkot roofing material                                                    ■Textured paintings/coatings
■Fire blankets                                                                     ■Vapor barrier
■Fire curtains/hose                                                           ■Linoleum floor tile & mastic-glue
■Fire doors                                                                          ■Linoleum flooring & mastic-glue
■Fireproofing                                                                     ■Vinyl wall coverings
■Furnace insulation                                                          ■Window glazing/window caulk

Source: https://www.health.state.mn.us/communities/environment/asbestos/products.html

Source:  https://www1.udel.edu/ehs/environmental/downloads/asbestos-faqs.pdf

Source:  https://www.buildwithrise.com/stories/asbestos-at-home

Asbestos Is Referred To As” “Friable” (may be shedding asbestos-fibers) When:

Image Source: Shutterstock

This Asbestos Is Likely Friable (Shedding Asbestos Fibers)

• It’s been disturbed.  Such as some original metal ductwork was removed.
• It’s damaged.
• It’s visibly deteriorated.
• If you have Asbestos with either of the problems above — it needs to be evaluated for removal.

Sources:

• Bill Brennan, VP of Brennan`s PEB & Associates, a Chicago-based asbestos abatement and removal firm.
• https://www.chicagotribune.com/news/ct-xpm-1992-05-15-9202130094-story.html
• https://www.caut.ca/docs/default-source/health-safety-fact-sheets/asbestos.pdf?sfvrsn=8
• https://inspectapedia.com/hazmat/Asbestos_Pipe_Insulation.php

Additional Asbestos Source:

• https://inspectapedia.com/hazmat/Asbestos_Pipe_Insulation.php
• https://inspectapedia.com/hazmat/Asbestos_Good_Condition.php
• https://inspectapedia.com/hazmat/Asbestos_Bad_Condition.php
• (R-Value): https://inspectapedia.com/insulation/Insulation-Values-Table.php#Asbestos

Mesothelioma Is A Form Of Cancer Caused By Inhaled Asbestos Fibers.

Mesothelioma Tumor(s) Can Form In The; Lungs, Abdomen, or Heart.

When anything containing asbestos is disturbed — microscopic asbestos fibers are released.  These fibers can remain airborne almost indefinitely and can travel great distances.

Asbestos Materials Are Either:

Nonfriable:

• Durable products keep asbestos fibers safely contained — as long as the materials are not damaged.
• Vinyl Asbestos (VAT) Floor Tile is one.
• Removing VAT Tile safely must be done by a qualified Asbestos-Abatement Contractor.

Friable:  Easy to break or crumble by hand.

• Friable asbestos materials easily release asbestos fibers into the air.
• Damaged or Deteriorated asbestos ductwork or pipe insulation would be an example.

Inhaled Asbestos Fibers Can Become Permanently Lodged Inside The Body — And Pose Serious Health Threats. 

• Asbestos is known to cause disease and cancers — and symptoms may not appear for up to 20 or more years later.
• There is no known safe level of asbestos exposure.
• Thousands of tradesmen who worked with asbestos-containing building-materials have died of related diseases.
• Even though the use of asbestos is now limited in the U.S. – thousands continue to die each year — due to past asbestos exposures.

Source: https://www.iowadnr.gov/portals/idnr/uploads/air/insidednr/asbestos/asbest_reg_brochure.pdf

Source: https://www.asbestos.com/mesothelioma/

Source: https://www.asbestos.com/blog/2018/07/13/asbestos-floor-tile-diy-removal/

This Section Does Not Apply To DFW

In Some Areas Of The U.S. Homes Built Up To The 1980s

 With Ductwork Located Under The Slab Foundation. 

May Have Ductwork Made Of Concrete — Containing 15-25% Asbestos. 

If it’s not been painted — A Black Stamp Reads: “JM-TRANSITE”.

Click Here To See A JM-Transite Stamp: JM Transite Stamp

Click On Link To See Transite Ductwork Under A Slab Foundation: Transite Ductwork Under A Slab Foundation

• Transite was created in 1929 — for asbestos-concrete building materials.  Transite™ is a Trademark of Johns-Manville Corporation.
• The word: “transite” is often (generically) used to describe products made of asbestos-cement (also called: “cement-asbestos”).
• Transite ductwork was popular in SOME 1960s & 1970s homes — with ductwork under their slab foundation.
• These homes’ heat vents are in the floors.  No attic ductwork homes have Transite.  It’s made of concrete and was be too heavy to be installed in an attic.

• Some People Incorrectly Describe: “under-slab ductwork” Generically As: “Transite”.
• Transite is a Brand Name owned by the Johns Manville Corporation.
• Most Under-Slab Ductwork Is Not Transite Brand. 
• A Home Inspector Can Determine The Material(s) Your Home’s Ductwork Is Made Of.

Source: https://inspectapedia.com/hazmat/Asbestos_Transite_Ducts.php

CAUTION: While Removing Transite Ductwork — Asbestos Fibers May Be Released Into The Air. 

This Work Must Be Performed By A Qualified Asbestos-Abatement Contractor.

Source: https://www.snipsmag.com/articles/94147-are-sub-slab-hvac-ducts-problematic

NOTE: IT’S NOT ADVISED TO HAVE TRANSITE DUCTWORK CLEANED. 

CLEANING DISTURBS TRANSITE DUCTWORK’S INTERIOR SURFACE.

DISTURBING TRANSITE DUCTWORK’S INTERIOR SURFACE — MAY RELEASE ASBESTOS FIBERS INTO THE AIR.

NOTE: Some Companies State That They Can Spray A Product Inside Transite Ductwork To Reduce The Risk Of Airborne Asbestos.

Because DFW Homes Don’t Have Under-Slab Ductwork,  We Have No First-Hand Knowledge Of These; Products, Services, or Contractors.

A Google Search May Locate Contractors In Your Area.

Al’s Plumbing, Heating & A/C in Plano, Texas provides maintenance & repairs for all brands of; Central A/C, Gas & Electric Furnace, and Heat Pumps.  Additionally, we sell and install new HVAC Systems from; American Standard (same company as Trane), Ameristar, Standard) and Coleman HVAC (same company as York).

Al’s also provides full-service plumbing maintenance, repairs, and replacements for every plumbing component in your home.  Al’s sells and installs gas & electric water heaters.  Al’s is near your home in; northeast Dallas, TX; Richardson, TX; and Garland, Texas.  We service all homes in southern Collin county Texas and northeast Dallas County, Texas with no additional travel charges.

Call Al’s today to discuss any concerns or problems you have with your HVAC System or Plumbing.

We’ll Arrange An Appointment At Your Convenience.