Guide to Identifying Asbestos Transite Chimneys, Flues, & Pipes in buildings
- Transite Asbestos Chimneys, Ducts Pipes: Asbestos Material Warnings
- Fire Clearance Requirements for & Label Descriptions of Asbestos Cement or Transite Heating Flues & Chimneys
- Safety hazards associated with asbestos cement transite chimneys & flues: carbon monoxide
- Safety hazards associated with touching, handling, or removing transite pipe cement asbestos chimneys, flues, pipes, or air ducts
- How to recognize asbestos containing transite pipe used in buildings for air ducts, vents and chimneys, and water piping
- Questions & answers abouthow to recognize asbestos or transite asbestos chimneys, HVAC ducts, flues, or pipes.
- References
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Transite asbestos chimneys, ducts, flues, pipes: this article assists in the recognition of transite pipe used for chimneys or heating flues and discusses potential hazards of this material when it is
found in buildings.
Transite pipe is an asbestos-cement product which was used for both HVAC ducts and for chimney or flue material to vent gas-fired appliances. 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. Cement-asbestos transite pipe was also used for water piping in some communities, as we discuss at Transite Pipe Water Supply Piping.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
Transite Asbestos Chimneys, Ducts Pipes: Asbestos Material Warnings
Because asbestos cement transite pipe chimneys may have operating and safety problems, concerns completely separate from asbestos handling questions, readers should see our chimney inspection suggestions at CHIMNEY INSPECTION DIAGNOSIS REPAIR.
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, dust or drinking water 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.
Watch out: Unsafe transite pipe heating flue vents may only be noticed by a careful building inspection such as shown in these rooftop photographs of a transite flue vent pipe which deteriorated, became swollen, and risk becoming blocked. In cold climates with these vents from the 1950's era, the real hazard is not so much asbestos fibers as the dangerous obstruction of the vent/flue by the deterioration of the interior of the pipe. [Photographs above and text just above on transite flue deterioration were provided courtesy of Roger Hankey].
In the transite chimney vent photo at above right we note that the exterior has been painted black. We don't know why, possibly the naturally gray-white transite flue was painted black for cosmetic reasons, or perhaps in an effort to slow down its surface deterioration.
Fire Clearance Requirements for & Label Descriptions of Asbestos Cement or Transite Heating Flues & Chimneys
In
use as a gas-fired appliance chimney/vent transite pipe may have been classed as a type "B" flue vent which required 1" clearance from combustibles in some jurisdictions. But as we indicate below, the fire clearance required for transite pipe or cement-asbestos pipe flues and chimneys varied from 1" to 3" and limited temperatures to 330 to 550 F depending on the clearance.
Ervin McKinney kindly provided a copy of a November 1948/1949 Underwriters Laboratories UL List of Inspected Gas, Oil, and Miscellaneous Appliances that includes specifications for Outlet and Vent Piping (540 116). That document indicates that
Vent piping of noncombustible, corrosion resistant material of adequate strength and heat-insulating value is acceptable according to Section 1006 of the Building Code Recommended by the National Board of Fire Underwriters (1949 Edition.) This piping is intended for use only with gas-burning appliances which produce flue gas temperatures not in excess of 550 F.
Unless otherwise indicated in specific listings, spacing to combustible material shall be not less than 1 in. provided that for vents of floor furnaces spacing shall be not less than 3 in. for a distance of not less than 3 ft. from the outlet of the draft hood.
Asbestos Cement Chimney & Flue Venting Products described in this 1948-1949 document include
Enderle, Inc., Ltd., Frank X., Los Angeles Calif.
Cylindrical outlet and vent piping of asbestos, sand, and cement, bell and spigot type.
Markings: "Enderle Vent" stenciled on each length of pipe and fitting.
Cylindrical outlet and vent piping of cement and asbestos having a galvanized iron outer jacket.
Markings: "Enderle Cased Vent" stenciled on each length of pipe and fitting.
Johns-Manville Corp. New York, NY., [Transite or cement asbestos flue vent and chimney piping description]
Consists essentially of cement and asbestos fiber built up in cylindrical and oval form: supplied with couplings, elbows, tees, joint cement, etc.
Suitable for use with 1-in. clearance to combustibles when flue gas temperatures do not exceed 330 F, or with 1 1/2-in. ventilated clearance when flue gas temperatures do not exceed 550 F.
Authorities having jurisdiction should be consulted regarding installation.
Marking: "J-M Transite Flue Pipe for Gas Venting" on each section of piping and on each fitting.
This same document also describes several other flue gas vent piping products made of vitreous coated steel, asbestos, sand, and cement, sand and pumicite with aluminum collar joints, sheet aluminum tube and asbestos insulating or steel spring spacer with an outer shell of galvanized sheet metal, and other aluminum and galvanized sheet metal piping.
See this PDF copy of 1948/1949 Underwriters Laboratories UL List of Inspected Gas, Oil, and Miscellaneous Appliances.
Carbon monoxide hazards with transite asbestos cement chimneys
Where transite pipe (asbestos-cement pipe) has been used as a building chimney to vent combustion gases, if the chimney becomes blocked there could be a dangerous carbon monoxide hazard in the building.
The transite pipe chimney - carbon monoxide hazard occurs when the (usually above-roof outdoor portion) of a transite pipe chimney becomes soft with age and exposure to weather, leading to swollen chimney sides and even chimney internal collapse.
The swollen and collapsing transite pipe chimney blocks the venting of exhaust gases from the building heating equipment.
Blocking the venting of exhaust gases, particularly for natural gas or LP gas fired heating appliances, is very likely to interfere with proper combustion at the appliance itself. In turn, this condition results in the production of carbon monoxide at high levels.
- Ultimately transite pipe cement asbestos chimney vent flue that becomes blocked creates a multiple safety hazard:
- Increased production of carbon monoxide at the heating appliance
- Failure to vent combustion gases fully outside the building
- Leakage of carbon monoxide gases into the building
See CHIMNEY INSPECTION DIAGNOSIS REPAIR and see CARBON MONOXIDE for more information.
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The transite flue vents, shown here are passing through a building interior closet.
Transite-asbestos piping used as plumbing vents or as chimneys for gas-fired appliances such as gas furnaces becomes swollen and deteriorated due to condensation of the water vapor in the combustion gases being vented, especially above the roof line or in a cold attic.
The acidic flue-gas-condensate combined with the effects of frost in cold climates causes a delamination and swelling and blockage
of the transite pipe chimney-flue.
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A blocked or constricted flue vent
pipe can cause production of dangerous or even fatal carbon monoxide gas in the building.
While the transite pipe shown above was in use as an exhaust flue (what is the fire rating and fire clearance required?), this
material was also used in some buildings for both exposed air ducts and for in-slab duct work (SLAB DUCTWORK) for heating and air conditioning systems, as shown in the photos below. |
Transite pipe, which contains significant percentage of asbestos fibers, was often used for heating ducts and on occasion heating
and cooling ducts in older buildings.
The transite pipe was used in a buried-in-slab construction methods which placed
the transite piping below or in a building floor slab, and asbestos-containing transite pipe ducts were also used
in exposed areas such as shown in the crawl space photographs above. [Photo above showing transite duct material is provided courtesy of Thomas Hauswirth, a Connecticut home inspector.]
Our photo below shows a transite (asbestos cement) chimney on the exterior of an older home. This chimney may be too cold to perform safely, especially if venting a gas-fired appliance. At CHIMNEY INSPECTION DIAGNOSIS REPAIR we describe chimney inspections in detail.
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Asbestos hazards of transite duct or chimney piping: Cementious duct material may contain asbestos. What is this "cement"
duct work made of? Cement and asbestos fibers.
How much asbestos is in Transite pipe? While it's cementious, transite ducts or even transite pipe used
for heating flue vents is a potential asbestos hazard in buildings. Transite pipe typically contains about
15% to 25% asbestos fibers, typically fibrous chrysotile asbestos.
A careful asbestos testing lab may report both fibrous and fragmented
asbestos which can occur in still smaller pieces (thus more easily remaining airborne and increasing human exposure to asbestos).
The balance will be cement and possibly other fibers or binders.
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Health Hazards from Handling Transite Pipe or Asbestos Cement Piping for Vents, Chimneys, or Air Ducts
Where are the chief health risks with cementious asbestos materials?
Transite pipe, whether it has been used as an air duct, flue vent, chimney, or water pipe, is still a cementious material that is unlikely to release high levels of airborne fibers when it is in good condition.
Touching transite pipe, or simply removing and disposing of an intact section of this material from a building by carrying it outside should not release a significant level of airborne asbestos fibers unless:
- The transite pipe was deteriorated, soft, friable - crumbly and easily made into powder and debris - this can happen where the material was exposed to weather such as the upper portion of a flue vent, plumbing vent, or chimney where it extends above a building roof or where transite air ducts were placed below a floor slab and exposed to water.
- The transite pipe was removed or attacked using power tools such as saws, grinders, or sanders, producing asbestos-containing dust
- The transite pipe was removed or attacked during demolition using hammers and similar implements
In summary, if it has become soft and friable, or if transite pipe is damaged or is cut mechanically (such as by using power equipment), friable, airborne asbestos fibers may
be generated - a health and potentially a costly cleanup concern.
Incorrect spellings of transite piping or transite duct material that we've seen include transit pipe, transit ducts,
Transide pipe, transide ducts, tranisite pipe, and transight pipe. "Transite" is the correct spelling.
Frequently Asked Questions (FAQs)
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.
ASBESTOS DUCTS, HVAC - Guide to Identification of Asbestos Materials On or In Heating and Cooling Duct Work: carbon monoxide hazards of transite chimneys and vents
ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY - Environmental Hazard Detection, Testing, Repair, Illness, Symptoms, & Prevention in buildings
IDENTIFICATION of ASBESTOS in buildings - Asbestos Identification in buildings: How to find & identify asbestos-containing materials
TRANSITE PIPE AIR DUCTS - Hazards of Asbestos-containing Transite Pipe HVAC Ducts: duct collapse, mold, radon, asbestos fiber release
Transite Pipe Chimneys & Flues - Guide to Identifying Asbestos Transite Chimneys & Flues & their Hazards in buildings
Transite Pipe Water Supply Piping - Guide to Identifying Asbestos Cement Transite Water Pipes & their Hazards in buildings
Roger Hankey is principal of Hankey and Brown home inspectors, Eden Prairie, MN. Mr. Hankey is a past chairman of the ASHI Technical Committee and the ASHI Standards Committee. Mr. Hankey serves as co-chairman of ASHI legislative committee, and has served in other ASHI professional and leadership roles. Contact: 952 829-0044 - hankeybrown@comcast.net
Ervin McKinney, a gas industry expert in Lorain OH, kindly provided this PDF copy of 1948/1949 Underwriters Laboratories UL List of Inspected Gas, Oil, and Miscellaneous Appliances. October 2010
June 1997 - Window Putty - OSHA case cites contractor for asbestos exposure during removal of window putty http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=NEWS_RELEASES&p_id=1091
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
Asbestos in Your Home U.S. EPA, Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
Asbestos products and their history and use in various building materials such as asphalt and vinyl flooring includes discussion which draws on Asbestos, Its Industrial Applications, D.V. Rosato, engineering consultant, Newton, MA, Reinhold Publishing, 1959 Library of Congress Catalog Card No.: 59-12535 (out of print, text and images available at InspectAPedia.com).
"Handling Asbestos-Containing roofing material - an update", Carl Good, NRCA Associate Executive Director, Professional Roofing, February 1992, p. 38-43
EPA Guidance for Controlling Asbestos-Containing Materials in buildings, NIAST, National Institute on Abatement Sciences & Technology, [republishing EPA public documents] 1985 ed., Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
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Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
 The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
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