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Photo Guide to Asbestos Paper Wrap on Air Ducts InspectAPedia®  -     How to recognize asbestos duct wrapping materials in buildings Photographs of asbestos paper duct wrap in buildings

This page illustrates asbestos paper duct wrap that was usually applied to the exterior of metal heating ducts in buildings prior to 1970. This document assists building buyers, owners or inspectors who need to identify asbestos materials (or probable-asbestos) in buildings by simple visual inspection. We provide photographs and descriptive text of asbestos insulation and other asbestos-containing products to permit identification of definite, probable, or possible asbestos materials in buildings.

While an expert lab test using polarized light microscopy may be needed to identify the specific type of asbestos fiber, or to identify the presence of asbestos in air or dust samples, many asbestos-containing building products not only are obvious and easy to recognize, but since there were not other look-alike products that were not asbestos, a visual identification of this material can be virtually a certainty in many cases.

Also see Asbestos HVAC Ducts a field identification guide to visual detection of asbestos in and on heating and cooling system ducts and flue vents.

© Copyright 2010 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

ASBESTOS PAPER DUCT INSULATION - Asbestos paper insulation on hot air heating duct or air conditioning duct exterior

This asbestos paper-like material is on the exterior of a hot air supply duct. On homes even into the 1960's we find this material used to seal joints in metal heating ducts. On older homes from perhaps 1920 the material was often wrapped around the entire duct exterior rather than simply at the joints. Since the duct is normally under positive pressure, any openings in the duct would be more likely to leak hot air out than to suck asbestos fibers into the air path. If on the other hand we found asbestos material in the air path or on a return duct it would be a more urgent repair topic.

Examples of Asbestos Suspect Material Commonly Found on Heating and Air Conditioning Systems in Buildings

We often see what may be asbestos containing insulating material on the heating system, including the following:

• Cement asbestos "millboard" used as a partial heat shield on wall/ceiling surfaces.
• White corrugated insulating material on and hanging from pipes, white paste material surrounding certain plumbing joints.
• White "paper" wrapped on outside of some heating ducts.
• White woven material used as flexible joint between some heating ducts.
• White woven material used as flexible joint in the vibration damper between air handler the duct work.

Heating and Cooling Duct Asbestos Paper Wrap Risks

The photograph shows asbestos paper duct wrap that has been damaged and is in poor condition. Is this material a hazard? Is it releasing asbestos fragments or fibers into the heating system air ducts? OPINION-DF: We have not located conclusive data or studies which evaluate hazards regarding specifically the presence of asbestos paper wrap on ductwork in residential buildings. Like other asbestos fibers in buildings from other sources, if disturbed and distributed in the living area of a building at levels above government standards, there is a potential health risk. We t is also a potential economic risk as future buyers may be concerned about this material. Disposal costs for this material are increasing. Depending on condition and location of asbestos material, treatment ranges from doing nothing to complete removal. Removal could involve significant costs.

General advice about asbestos suspect paper wrap material on heating or cooling duct work: You should obtain proper technical information and health and safety guidelines before attempting to do anything with this material. It is the breathing of fibers when this material is disturbed, not it's mere presence, which is considered a health risk. When the material is not found in living areas in poor condition treatment is not usually an emergency and you have time to become informed, obtain estimates, and select an appropriate course of action.

If asbestos materials are inside the duct work, such as used for lining of a stud or floor joist bay which serves as an air duct, or perhaps where used as the vibration damper material connecting an air handler to the supply plenum of a system, because of the possible release of fibers continuously and directly into the path of moving air in the building, this material should be removed.

If asbestos materials have been disturbed inside a building without proper containment and cleanup, additional evaluation of the level of asbestos particles in building may need to be evaluated as additional expert cleaning might be needed.

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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

ASBESTOS IDENTIFICATION IN BUILDINGS
Asbestos Risk Assessment
Asbestos in Good Condition
Asbestos in Poor Condition
Asbestos Removal, Amateur, Incomplete
Asbestos Foamed-Over
Asbestos Air Ducts
Asbestos Air Duct Vibration Dampers
Asbestos Pipe Insulation
ASBESTOS REGULATION Update
Asbestos Roofing Materials
Asbestos Siding Materials
Asbestos in unusual places
Carbon Nanotube Materials
Ceiling Tiles Containing Asbestos
Fireproofing containing Asbestos
Floor Tiles Containing Asbestos
Paper Duct Insulation Containing Asbestos
Transite Pipe Air Ducts
Transite Pipe Chimneys & Flues
Transite Pipe Water Supply Piping
Urea Formaldehyde Foam Insulation UFFI
Vermiculite Insulation Containing Asbestos
Other Asbestos-Containing Materials
Asbestos Under the Microscope

Insulation Material Identification Guide
Asbestos-Free Insulation Materials
  Asbestos Pipe Insulation
  Balsam Wool Batt Insulation
  Cotton Insulating Batts
  Cellulose loose fill insulation
  Concrete insulation, light-weight
  Fiberglass Insulation
  Foam Board Insulation
  Foam Insulation Types - Visual Id
  Homasote & Other Insulating Board
  Icynene Foam Spray Insulation
  Insects & Foam Insulation
  Mineral Wool - Rock Wool Insulation
  Mold in Fiberglass Insulation
  Mold in Foam Insulation
  Paper Duct Insulation
  Perlite Insulation
  PHENOLIC FOAM INSULATION
  POLYISOCYANURATE FOAM INSULATION
  POLYISOCYANURATE FOAM BELOW SLABS
  POLYSTYRENE FOAM INSULATION
  SUPER HI-R INSULATION
  Vermiculite Insulation

• 3/07: thanks to Gary Randolph, Ounce of Prevention Home Inspection, LLC Buffalo, NY, for attentive reading and editing suggestions. Mr. Randolph can be reached in Buffalo, NY, at (716) 636-3865 or email: gary@ouncehome.com
• 06/07: thanks for photographs of transite asbestos heating ducts, courtesy of Thomas Hauswirth, Managing Member of Beacon Fine Home Inspections, LLC and (in 2007) Vice President, Connecticut Association of Home Inspectors Ph. 860-526-3355 Fax 860-526-2942 beaconinspections@sbcglobal.net

More Information on Building Diagnostic Inspections and Repairs

• Asbestos: How to find and recognize asbestos in Buildings - visual inspection methods, list of common asbestos-containing materials
• Asbestos HVAC Ducts and Flues field identification photos and guide
• Fiberglass: Indoor Air Quality Investigations: Health Concerns About Airborne Fiberglass: Fiberglass in Indoor Air from HVAC ducts, and Building Insulation
• Enviro-Scare: Electric Power Lines, Electromagnetic Fields, Cancer Risk, & "Enviro-Scare" - The Normal Curve Cycle of Public Fear of Environmental Issues
• Dust from the World Trade Center collapse following the 9/11/01 attack: the lower floors of this building contained spray-on fire-proofing asbestos materials.
• Asbestos Information Links: Asbestos Detection, Testing, Recognition, Hazards, Field Photos, and Information Sources, including health-related links such as legal services and information about mesothelioma and other cancers.
• Asbestos Identification and Testing References
• Asbestos Identification, Walter C.McCrone, McCrone Research Institute, Chicago, IL.1987 ISBN 0-904962-11-3. Dr. McCrone literally "wrote the book" on asbestos identification procedures which formed the basis for current work by asbestos identification laboratories.
• Stanton, .F., et al., National Bureau of Standards Special Publication 506: 143-151
• Pott, F., Staub-Reinhalf Luft 38, 486-490 (1978) cited by McCrone

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