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Asbestos electrical insulation:
Asbestos insulation history, manufacture, visual identification includes asbestos used in electrical wiring and appliances. Here we describe how to recognize asbestos-based or asbestos containing electrical insulation materials in products & buildings - a visual guide to identifying asbestos in buildings.
Page top photograph: asbestos insulation on electrical wiring in a theater.
This articles series about the manufacture & use of asbestos-containing products includes detailed information on the production methods, asbestos content, and the identity and use of asbestos-containing materials. Page top photo shows asbestos used in an electrical motor.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Asbestos Electrical Insulation Materials History & Manufacturing Processes
One of the major uses for asbestos paper as well as for
such forms of asbestos as yarn, tape, lap, and loose fiber is
in the field of electrical insulation. Asbestos was used in both higher voltage AC or DC electrical wiring as well as in low voltage wiring products such as telephone cabling.
[Click to enlarge any image]
The main reasons for
the use of asbestos are its fire and heat resistance,
electrical insulation properties, acid resistance, and durability.
Electrical insulation is also used to protect the surfaces
of conductors from such adverse conditions as moisture
and chemicals, and to fill spaces where corona discharge
is liable to occur.
In electrical applications, asbestos insulation is used with
low iron content. All grades of crude and milled chrysotile
fiber are predominately used.
The lowest iron content fibers
for use in the electrical field are available from ore deposits
in the North American Continent. ASTM specifications list
the total iron content for electrical grade products. Details are
List of products using asbestos electrical insulation
Large quantities of asbestos are used to cover electrical
wire in the traction type of electric motors and coils where
there is a possibility of rising temperature damaging ordinary
The general use of asbestos electrical
insulation includes ordnance equipment (aircraft, missiles,
etc.) oil burners, heating and cooking apparatus, lighting
equipment, agricultural machinery, construction and mining
machinery, hoists, oil field machinery, machine tools, portable
tools, bakery machinery, food products 'machinery,
textile machinery, paper industry equipment, pumps and
compressors, conveying equipment, blowers and fans, trucks
and tractors, industrial ovens and furnaces, mechanical
stokers, computers and cash registers, vending machines,
laundry equipment, vacuum cleaners and units, refrigeration
and air conditioning units, motors and generators,
power transformers, switchgear controls, welding units, insulated
wire and cable, lamps, radio, TV and radar units,
x-ray units, railroad units, dental units, and signs and
Lightweight asbestos insulation is of primary importance
on Naval and Maritime ships. Navy cable insulation is of
particular importance; it is a combination of asbestos paper
and textile products (lap, tape, etc.)
In the manufacture of multi-conductor cables, the single
or paired conductors are cabled into required multiples, together
with cushioning fillers in the valleys. These fillers are
generally made with asbestos roving.
Specifications for Asbestos-Based Electrical Insulation Materials
Classification of electrical insulation by the American
Institute of Electrical Engineers (AIEE) follows:
Classes of Electrical Insulation Materials
Organic, not impregnated
Inorganic, organic binder
Inorganic, silicone binder
Notes to the table above
Watch out: This data is circa 1959 from AIEE and is not current; therefore the table is provided for historic reasons and not as a current standard for electrical insulation products.
Another classification which includes asbestos-electrical
insulated products is given by the Underwriter's Laboratories,
Inc. This laboratory classifies asbestos electrical
insulating material as asbestos-insulated wire (460 12) and
as asbestos-varnished cloth wire (460 13).
Type AA, with an asbestos braid and asbestos insulation
Type Al, with impregnated asbestos insulation
Type AlA, with asbestos braid and impregnated asbestos
Asbestos-Varnished Cloth Wire (460 13)
Type AVA, An asbestos braid: an insulation consisting of
varnished cloth and impregnated asbestos.
Type AVB, A plain [flame?] -retardent cotton braid: an insulation
consisting of varnished cloth and impregnated asbestos.
Type ABL, A lead covering: an insulation consisting of
varnished cloth and impregnated asbestos.
Watch out: by visual inspection I don't think we can distinguish cloth, non-asbestos wiring insulation of this age from Type AVB, A plain [flame?] -retardent cotton braid: an insulation
consisting of varnished cloth and impregnated asbestos. The wire shown above is discussed at OLD ELECTRICAL WIRING TYPES
Data pertaining to electric shipboard cable which includes
asbestos is given in the "Cable Comparison Guide," NAV-
SHIPS 250-660-23 (1956) published by Bureau of Ships,
Navy Department, Washington 25, D. C. and available
through Government Printing Office.
The data pertains
to Government procurement specifications MIL-C-915A
(Ships), MIL-C-2194B (Navy), MIL-C-2681 (Ships), and
MIL-W-16878B (Navy). All cables are identified by types.
The letters listed under types identify the first letters of the
words used in describing the cable. Other letters identify
construction of the cable. Some of these cables which incorporate
asbestos are identified as follows:
DFPA, Double conductor, flame proof, armored: Natural
rubber of asbestos-varnished cambric-asbestos insulation
depending on size, cabled with fillers, belt, armored.
DHFA, Double conductor, heat and flame resistant, armored:
Size 3, 4 and 9 with synthetic resin and felted asbestos
insulation; sizes 14 and larger with asbestos-varnished
cambric-asbestos insulation, cabled with fillers, belt, impervious
DHFTA, Double conductor, heat and flame resistant,
thin wall, armored: Thin wall synthetic and felted asbestos
insulation, cabled with fillers, binder, impervious sheath,
FHFTA, Four conductor, heat and flame resistant, thin
wall, armored: Thin wall synthetic and felted asbestos, insulation,
cabled with fillers, binder, impervious sheath,
Asbestos papers are very popular for use in the manufacture
of miniature electrical component units. Miniature
transformers can use asbestos papers. A 30 per cent reduction
in weight has been obtained in Class-B transformers.
I [DF] have also found asbestos-paper insulated electrical wire inside of some older electrical appliances such as stove tops and toasters though more often we found braided asbestos cloth insulated wire in those locations.
World War II initiated many development projects specifically
for developing inorganic paper products. Prior to
1940, no inorganic papers were commercially available. At
present, there are four basically different types of inorganic
papers commercially available; i.e., asbestos, mica, glass,
Asbestos papers are manufactured by Johns-
Manville, Inc. under the trade name "Quinterra" or "Quinorgo"; by Raybestos-Manhattan, Inc. under the trade name
"Novabestos"; and by General Electric Co. under the trade
These basic paper products are available
in many different forms which include combinations of
asbestos-glass, asbestos-mica, papers backed with or sandwiched
between other types of papers or fabrics and held
together by an oleoresinous varnish, shellac, silicone, rubber,
or other composite insulation structures. These combinations
provide for increased tensile strength which is desirable
in many of the cable or wire taping operations.
The chief function of asbestos [in electrical applications] is that of a separator or as
a wrapping for wire insulation. Untreated paper is roughly
equivalent to air as an insulator; when it is completely dry
its resistivity is good.
Untreated paper can contain moisture
since it has the characteristic of absorbing moisture from the
air—a characteristic typical of other paper products. It is
usually treated with a varnish or lacquer in order to eliminate
the moisture problem. Where high temperature requirements
are of prime interest, the paper is treated with
silicone varnishes or fluorocarbons.
In the manufacture of asbestos paper, there is always
continued interest and development in producing open asbestos
fibers. Various methods of manufacture and various
equipment are used in order to fiberize bundles of asbestos
fiber. By opening the fibers, entrapped undesirable magnetite
can be removed.
Manufacturing processes have also
been developed which permit uniform blending of asbestos
fiber with such synthetic fibers as glass. These types of
products are used by electrical insulation manufactures and by the manufacturers of reinforced plastics and filters.
"Quinterra" is a pyrolysis-resistant electrical insulation
made of highly purified asbestos. These electrical insulations
greatly extend the life of electrical equipment. By permitting
magnetic units to operate at higher temperatures, they
promote savings in space, weight and materials.
The asbestos products enable electrical apparatus to withstand
higher overloads; thus, they reduce the necessity for standby
equipment. Their thin layers require less time and labor to
apply and occupy less space than the extra thicknesses formerly
employed to compensate for the loss of dielectric
strength caused by heat.
(Courtesy Johns-Manville Corp.)
Figure 6.1. Installation of Quinterra wrapped coils in electric motor
armatur e[click to enlarge]
In transformers, their uses include barriers, core tubes,
spacer sticks, end packings, interlaminates, interlayers, and
wrappers. They have replaced metal cores in some resistors
and conserve insulation in others.
In magnets, they insulate
the ribbon coils, and form liners, spacers, and wrappers.
Both wires and cables are wrapped with "Quinterra" and
"Quinorgo" Typical motor wire insulation is shown in
Patent 2,626,213 describes a unique method of dispersing
and forming asbestos papers. The Novabestos paper products
produced are characterized by their ability to stretch
and distort, both dry and wet, to a much greater extent than
The smooth asbestos fibers in the paper
allow more flow and better packing properties than the
commercial organic paper products.
The Novabestos paper machine developed specifically for
producing asbestos paper is similar in many respects to
the conventional Fourdrinier machine. The asbestos pulp is
picked up by a wire screen and carried over flat boxes operating
under a vacuum of 2 to 8 in. mm.
The flat boxes remove
60 to 70 per cent of the water from the slurry. The next step
in drying is a suction transfer roll operating under a vacuum
of 12 to 15 in. mm. In this operation, another 5 to 10 per
cent of water is removed.
From the suction transfer roll, the
paper goes over a steam-jacketed drying roll and then over
a windup drum.
The finished paper product has the appearance
of snowy white paper.
Reader Question: does this house wiring contain asbestos?
I was curious if I could post [this photo of old house wiring at an electric light fixture] in order to ID potential asbestos insulation.
The pictures are of a closet light fixture I was uninstalling. - M.C. 6 Feb 2016
Most likely those are conventional fabric (non-asbestos) insulated wires.
Fabric covered (non-asbestos) electrical wire that was black or silver was often comprised of asphalt-impregnated cloth on both the wire jacket and the wires themselves, with the wire insulation made of fabric-covered rubber. Do you also have photos of the markings on the wire's outer jacket?
The asbestos-based electrical wire insulation I've seen appeared as white or gray fabric (theater wiring such as is shown at the top of this page) or in a harder asbestos-impregnated plastic or rubber insulation on wires used in high temperature appliances such as toasters, range tops, ovens, clothes dryers.
Watch out: however as you'll read in the article above there was asbestos-cloth insulated wire of several types, and more-difficult to distinguish by eye alone is asbestos-impregnated cotton fiber wire insulation.
The amount of debris removed by trimming the wire is probably trivial in any event.
Reader Question: did house wiring ever contain asbestos?
I was wondering if house wiring ever contained asbestos. The wiring in my home appears to have an asphalt impregnated type covering almost looks like a snake skin. Could this contain asbestos? - D.T., Canada 10/4/2013
A competent onsite inspection by an expert usually finds additional clues that would permit a more accurate, complete, and authoritative answer about wiring (noting any markings, exact composition of its insulation, and perhaps data about its age) than we can give by email alone. You will find additional depth and detail in articles at our website.
That said I offer these comments:
Asbestos was indeed used in electrical wiring insulation, as discussed beginning
Asbestos was in particular, more widely used in a more pure form in certain electrical wires exposed to high risk (inside of heaters, toasters, electric stoves, theatre wiring).
I would like to see sharp photos of your wiring, its external jacket, cross section of the insulation, and if occasion permits, an actual sample - those details would permit further comment or even testing of the material.
Depending on the age and appearance of the wiring about which you ask, it may be appropriate to treat it as PACM - presumed asbestos containing material. But don't panic. Usually asbestos hazards are minimized by leaving PACM alone unless it is friable, already damaged and / or subject to damage and is in an occupied space.
I suspect that unless there is a demolition project in progress, the asbestos exposure hazard from asbestos-containing residential electrical wiring is very low, perhaps below the limits of detection, both because of low friability of the typical (excluding my list above) application and insulation materials, and because wiring is normally enclosed in wall, floor, or ceiling cavities.
Reader Question: asbestos used in vacuum cord SVT electrical cords?
(May 2, 2014) Frank d said:
Does vacuum cleaner cord SVT have abestos? Or has it ever contained abestos?
Svt cord is a type of UL cord that they use in vacuums it's probably highly unlikely that they use asbestos in this type of application. Ami I right?
Asbestos was used in some electric wire insulation such as high temperature wiring in heating devices and stoves and in theater wiring.
Dillon (1942) and other of our citations given below describe widespread use of asbestos in electrical appliances, devices, and in their wiring and line cords.
So SVT electrical cords are basially a cord with a thinner insulating jacket, intended for use on vacuum cleaners - appliances that often want to use a spring-loaded spool to re-wind and store the cord when it's not in use. That thin-ness limits the use of the power cord to just certain applications.
Weber (1997) cites SVT components in older guitar amps that did contain asbestos but that asbestos use was in the amplifier's structure.
I don't know that that application speaks to being able to assert the use or non-use of asbestos whatsoever. My OPINION is that where heat is an extra concern (such as toasters) we might be more likely to find that asbestos was used in an appliance electrical cord. Heat may indeed be a concern, or rather heat tolerance, in a power cord that has also to use a thin insulating jacket for other reasons.
The specifications for electrical wire insulation have much to do with tolerating heat as well as other factors (flexing in power cords, moisture resistance, etc).
Asbestos was in fact mixed with rubber in some applications.
You might approach the question of whether a specific power cord contains asbestos more easily by stating the product's name, model, and date of manufacture, and if available the manufacturer could certainly answer the question. The alternative is to have a sample tested.
Possible Asbestos Insulation in Power Cable for Electric Welder
The damaged power cable shown above was used with a 1970's electric welder.
Beneath the heavy rubber exterior of the welder power cable we see a cloth fabric that might be an asbestos fabric needed for extra heat resistance. - reader anon by private email 2017/04/18
I was curious as to what it was, and it's 90% cellulose insulation as tested by Western Analytical Laboratories. The test for asbestos cost $30. U.S.D.
Now the $150 worth of scrap copper is safe to scrap. - Anonymous by private email 2017/04/25
Question: was asbestos used in telephone cabling or wiring?
2016/01/04 Mike said:
Would asbestos ever had been utilized in the telephone cable that has hundreds of copper conductors wrapped in paper and covered with a lead sheathing? Trying to know if this cable can be easily recycled.
I would not rule out asbestos on cable insulation, telephone or other wiring, depending on where it was intended to be used. Asbestos was used for fire protection in some telephone cabling as early as 1901 and continuing at least into the 1970's including as an alternative to the jute core wrap used on wiring that may have been then encased in lead or other metal piping.
I have found research describing asbestos exposure of telephone linemen, suggesting that asbestos was certainly used in some telephone cabling. And some patent disclosures concerning telephone cabling also included asbestos materials.
Research citing use of asbestos in telephone cabling, wiring, and core wraps
Meguellati-Hakkas, Djamila, Diane Cyr, Isabelle Stücker, Joëlle Févotte, Corinne Pilorget, Danièle Luce, and Pascal Guénel. "Lung cancer mortality and occupational exposure to asbestos among telephone linemen: a historical cohort study in France." Journal of occupational and environmental medicine 48, no. 11 (2006): 1166-1172.
Anderson, Robert W., and Robert E. Smith Jr. "Radiation resistant cable and method of making same." U.S. Patent 4,051,324, issued September 27, 1977.
Brorein, William J. "Flame retardant inside wiring cable made with an annealed metal sheath." U.S. Patent 4,154,976, issued May 15, 1979.
Joseph, Lemieux Roger. "Filled cable core with foraminous core wrap." U.S. Patent 3,681,510, issued August 1, 1972.
Saylor, Frank D. "Fire-protector for telephone-cables." U.S. Patent 688,970, issued December 17, 1901.
Question: does Cres Flex NMC wire contain asbestos ?
My house contains Black and Silver braided cloth wiring with the markings CRESFLEX 12 AWG printed on them. The actual conductors are coated in rubber or PVC and there is no ground. Does this wiring contain Asbestos? - posted at this web page 2017/12/23
It would be unusual to find asbestos insulation on or in Cres Flex residential electrical circuit wiring.
More likely you're seeing a fabric, perhaps with an asphalt impregnation and silver top coat. Naturally nobody can promise you a firm answer about asbestos content in an un-seen, un-tested material in an unknown building.
Still the risks are likely to be very low unless you're making a dusty mess.
Illustration above: Advertisement for Crescent Metallic-Sheathed Wire appearing in
Salisbury, Frank. "The inhabitants of Mars." Engineering and science 18, no. 7 (1955): 23-32. This is NOT Cres Flex but was produced by the same company and without mention of use of asbestos in the wire insulation.
Cres Flex Electrical Wire History & Components
Cres Flex was produced by Crescent Insulated Wire & Cable who also produced a metallic sheathed wire depicted in an advertisement we show below.
Cres Flex, also written Cresflex in some literature, is a specific brand produced by the Crescent Insulated Wire & Caboe Company, a Trenton New Jersey company. Cres Flex was first trademarked in 1936.
A predecessor of later plastic-insluated electrical wire (NMC or “non-metallic cable”), Cres Flex is an older form of flexible-jacketed non-metallic electrial wire using a specially-treated fabric braid insulating jacket. Such wire has also been referred to more-generically as “Romex” and Loomwire.
Reader request for photos: photographs of Cres Flex electrical wire are needed for this article - please use the page top or bottom CONTACT link or post photos as a comment at the end of this page. - Editor
Definition & Ingredients of Standard Non-Metallic Sheathed Cable - NMC
Nonmetallic Sheathed Cable: This material, known by such trade names
as Romex, Cresflex, Loomwire, etc., is shown in Fig. 4-5, and consists of
two or more Type R or Type T wires ; over each wire is a paper braid, and
over all is a spiral wrapping of paper. The wires are then enclosed in an
overall outer braid of cotton, which is treated with moisture-resistant and
The spaces that would otherwise be empty are
filled with a jute or similar cord. - from Richter, H.P., “WIRING SIMPLIFIED”, [PDF] Park Publishing Co., original (C) 1954, re-issued in multiple editions, 25th Ed., based on the 1956 U.S. National Electrical Code.
By "Standard NMC" I mean to exclude high-temperature-resistant or heat-resistant or fire-resistant electrical wiring such as might be used in electric stove tops or heating appliances where asbestos might have been used.
This same text cites the use of asbestos in high temperature application such as the manufacture of Type SP wires:
Fig. 4-7. In Type SP, the wires are imbedded in rubber. The cord is durable, attractive.
A really tough and knock-about cord is Underwriters' Type S shown in
Fig. 4-8. Each wire is rubber-insulated; the two wires are then bundled
into a round assembly, the empty spaces being filled with jute or paper twine
to make it round. Over all comes a layer of tough, high-grade rubber. Type
SJ is similar except that the outer layer of rubber is thinner.
For flatirons and other devices delivering considerable heat, a special
cord is required known as "heater cord." The most common type is Type
HPD and Fig. 4-9 shows its construction. A layer of asbestos is applied
over each wire before twisting. Over all comes a layer of rayon or cotton;
the cotton is by far the more durable.
Cres Flex Electrical Wire History via Patent Search - NMC wire without asbestos
A patent search and literature search performed on 12/24/2017 did not find the word “asbestos” appearing in CresFlex patents.
We searched for use of the word Asbestos in Cres Flex wire product descriptions, searching for patents assigned to Crescent Insulated Wire & Cable CO., in Trenton NJ
The word “asbestos” was not found in the following
Kinniburgh, Donald P., ”Cable construction." U.S. Patent 2,924,141, issued February 9, 1960. Assigned to Crescent Company Inc
Pearson, Stanley. "Round electric cable for severe environmental operation and method of manufacture thereof." U.S. Patent 3,809,802, issued May 7, 1974. Assigned To Crescent Insulated Wire & Cabl.
Robinson, Edmund L., ”Electric cable for high temperature operation." U.S. Patent 3,413,408, issued November 26, 1968. Assigned To Crescent Insulated Wire & Cabl.
Stdaller, Alfred W. “Apparatus for mixing the compounding agents of plastic powders." U.S. Patent 2,689,713, issued September 21, 1954. Assigned To Crescent Insulated Wire & Cabl.
Other NMC patents without asbestos:
Berman, Joseph E., and Jr Harry A. Toulmin. "Wire rope and process of manufacturing same." U.S. Patent 2,509,894, issued May 30, 1950. assigned to Ind Metal Protectives Inc
Note that other patents by other companies, Not CresFlex do include asbestos in wire product descriptions, typically for special applications. Examples are given below
Cres Flex Electrical Wire Trademark Information
On Monday, May 04, 1936, a U.S. federal trademark registration was filed for CRES FLEX by CRESCENT INSULATED WIRE & CABLE CO. INC., TRENTON. The USPTO has given the CRES FLEX trademark serial number of 71377968.
The current federal status of this trademark filing is EXPIRED. The correspondent listed for CRES FLEX is ? of *****, *****, ***** ***** . The CRES FLEX trademark is filed in the category of Houseware and Glass Products .
The description provided to the USPTO for CRES FLEX is NONMETALLIC SHEATHED CABLE FOR CARRYING ELECTRICAL CURRENTS. - Cres Flex Trademark Information, Trademarkia.com , Retrieved 2017/12/24, original source: https://www.trademarkia.com/cres-flex-71377968.html
Word mark: CRES FLEX
Status/Status Date: EXPIRED 6/10/1997
Serial Number: 71377968
Filing Date: 5/4/1936
Registration Number: 0338306
Registration Date: 9/1/1936
Goods and Services: NONMETALLIC SHEATHED CABLE FOR CARRYING ELECTRICAL CURRENTS
Last Applicant/Owner: CRESCENT INSULATED WIRE & CABLE CO. INC. TRENTON
Research Citations Indicating Use of Asbestos in Electrical Wiring & Components
Avidiya, James E. "Combination door and ironing board." U.S. Patent 3,170,417, issued February 23, 1965. used asbestos in its electrical outlet.
Baddour, Joseph S. "Electrical face treating mask." U.S. Patent 2,028,889, issued January 28, 1936. used asbestos on electrical conductors in this product.
Baisch, Thelma E. "Electrically heated gravy warming ladle." U.S. Patent 4,005,310, issued January 25, 1977. The gravy warming ladle included asbestos wire insulation.
Bakke, Allan P. "Electric blood warmer utilizing a metallic ribbon-flow cartridge." U.S. Patent 4,782,212, issued November 1, 1988. included use of asbestos
Booker, Aylwin R. "ELECTRICALLY CONDUCTIVE." U.S. Patent 2,715,668, issued August 16, 1955. describes production of electrically conductive asbestos panels
Brister, Joseph E., Powell George M., ”Method of producing sealed cables." U.S. Patent 2,427,507, issued September 16, 1947. Assigned to Carbide & Carbon Chem. Corp.
Excerpt: A wrapping 21 of asbestos impregnated with a fiameproof sealing composition is then applied in the conventional manner, and will cause the sealing composition on the outside of aid fillers to form a tight seal with said wrapping material. may be applied another coating of the sealing composition from the cone 2!, if desired. This patent cites Crescent IWC US3809802 *
Burt, Guy H. "Electrical plug." U.S. Patent 2,128,883, issued August 30, 1938. used asbestos in the cord plug as an insulator
Callahan, James J., and John P. Snow. "Electrical cable adapted for use on a tractor trailer." U.S. Patent 3,993,860, issued November 23, 1976. used asbestos in the electrical cable.
Cunningham, James D. "Electrically operated impact tool." U.S. Patent 4,323,127, issued April 6, 1982.
DICK, TALBEBT M. "Face mask or like." U.S. Patent 1,820,602, issued August 25, 1931. used asbestos Excerpt:
4. Embedded in the face and neck portion ofthe mask is a circuit of resistance wire 13 extending in spaced. convolutions 90 throughout the area. of the face and neck-portions and which has its length of coil construction wound around a cord 14 of asbestos or like flexible material. B this arra ment of parts the convolutions will not only t completely surrounded by the rubber portion of the invention but will be held apart one from the other.
Dillon, Ernest E. "ELECTRIC VACUUM FLUE CLEANERS." U.S. Patent 2,281,144, issued April 28, 1942. Describes use of asbestos in the vacuum cleaner motor assembly: Excerpt:
An asbestos sheet 30 is interposed between the housing rear wall I4 and the housing fiange i5 and is provided with a central opening 3| through which the motor shaft 24 projects. The asbestos sheet prevents heat from gaining access to the motor and damaging the windings.
Dublirer, Kobert. "Collapsible heating pad for travelling." U.S. Patent 3,130,289, issued April 21, 1964. Describes use of asbestos wrapping in electrical components of a heating pad
Elsenheimer, Charles W. "Electric flatiron and the like." U.S. Patent 2,353,151, issued July 11, 1944. Cites asbestos electrical cord insulation as an exgternal sheath
"Electrical steam generator." U.S. Patent 2,140,516, issued December 20, 1938. Cites asbestos used in electric heater elemnents and wicks.
Governale, Anthony J., and Rolf A. Zurwelle. "RADIANT ENERGY WARMER-DRIER FOR TEXTILE ARTICLES." U.S. Patent 3,626,152, issued December 7, 1971. used asbestos sheets that were electrically conductive
Grabner, Floyd V. "Electrically heated bath drying device." U.S. Patent 3,418,452, issued December 24, 1968. describes use of asbestos on electrical components
Heiser, Myron G., and Wheeler C. Gilbert. "Attachment plug." U.S. Patent 2,343,664, issued March 7, 1944. used asbestos fluffed up layers
Herbert, William J., Bruce E. Klipec, and Clifford R. Stine. "Wire and cable." U.S. Patent 4,096,346, issued June 20, 1978. Describes use of asbestos electrical wire insulation as a fire barrier.
Irrgang, Louis J. "Strain relief for electrical conductors." U.S. Patent 2,420,826, issued May 20, 1947. Cites use of asbestos tape around electrical conductors.
Kalichmann, Isidore, and David Weissberger. "Mechanized electrically heated windshield cleaner." U.S. Patent 3,935,425, issued January 27, 1976. used an asbestos scraper
Lewis, Edward H. "Electric cord set." U.S. Patent 2,091,824, issued August 31, 1937. Cites use of asbestos electrical cord insulation.
Musgrave, Harrington Le B. "Electric heating devices and the like." U.S. Patent 2,889,439, issued June 2, 1959. Cites asbestos electrical panels in electric heaters.
Pedlow, J. Watson. "Electrical arc and fire protective sheath, boot or the like." U.S. Patent 4,018,983, issued April 19, 1977. Cites asbestos used in electrical cabling and power cords
SACKERMAN, ERNEST A. "DEVICE FOB." U.S. Patent 1,316,190, issued September 16, 1919. used asbestos components in a devie for thawing frozen pipes Excerpt:
Extending over the entire inner face of each section and suitably fastened thereto, is a layer of asbestos 6 or other heat nonconductive material. Stretched over the outer face of the asbestos layer to extend longitudinally thereover and substantially parallel to each other are a number of coiled incandescent wires 7 suitably fastened in position and insulated by suitable means (not shown) from the sections or shells 1, 1,
which coils constitute the heating means and correspond with those usually employed in the well known bread toasters or other electric heating devices.
These wires, when an electric current is passed therethrough, will be heated to red heat which will be utilized for thawing the gas or water pipe.
Scott, Mindy. "Electrically heated vaporizing device." U.S. Patent 3,152,240, issued October 6, 1964. used asbestos as follows: Excerpt:
The insulation should be adequate to prevent the heating element 23 from causing the transmission of an unsafe quantity of heat to the bottom support 15, top flange 21 or to base 14. I prefer to use a layer of /8 inch thick ness asbestos 27 in conjunction with a layer of inch thickness spun glass 28 for this purpose.
Shomphe, George J. "Electrical resistance heating articles." U.S. Patent 3,417,229, issued December 17, 1968. Cites unraveling asbestos insulation exposing heater elements. Walter, Jacobsen. "Electrically heated flying suit." U.S. Patent 2,329,766, issued September 21, 1943. Cites use of asbestos padding in an electrically-heated flying suit.
Weber, Gerald. Tube Amp Talk for the Guitarist and Tech. Hal Leonard Corporation, 1997 Cites asbestos board used in guitar amps.
Werner, Arthur M. "Cordless electric iron." U.S. Patent 2,714,650, issued August 2, 1955. used asbestos in the iron stand
Wilkoff, Howard M., ”Electric cord or cable." U.S. Patent 2,260,761, issued October 28, 1941. Assigned to American Steel & Wire Co.
Excerpt: The braid jacket 4 may be braided from cotton, asbestos, silk, rayon, linen, glass, jute, etc.
Williamson, Val K. "Combined table and food warmer." U.S. Patent 2,866,956, issued December 30, 1958. used asbestos in electrical components in heating plates of this electrical appliance.
Continue reading at ASBESTOS FRICTION MATERIALS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
 Asbestos, its Industrial Applications, D.V. Roasato, engineering consultant, Newton MA, Reinhold Publishing Co., NY, 1959, Library of Congress Catalog No. 59-12535. We are in process of re-publishing this interesting text. Excerpts & adaptations are found in InspectApedia.com articles on asbestos history, production & visual identification in and on buildings.
 "Asbestos in Plastic Compositions", A.B. Cummins, Modern Plastics [un-dated, pre 1952]
 "Asbestos in Your Home," Spokane County Air Pollution Control Authority, Spokane WA 509-477-4727 www.scapa.org provides a one-page image, a .pdf file drawing of a house warning of some possible sources of asbestos in the home. The sources are not ranked according to actual risk of releasing hazardous levels of airborne asbestos fibers and the list is useful but incomplete.
 The US EPA provides a sample list of asbestos containing products epa.gov/earth1r6/6pd/asbestos/asbmatl.htm
 "Characterization of asbestos exposure among
automotive mechanics servicing and handling
asbestos-containing materials", Gary Scott Dotson, University of South Florida, 1 June 2006, web search 3/9/2012 original source: scholarcommons.usf.edu/cgi/viewcontent.cgi?article=3505&context=etd [copy on file as /hazmat/Automotive_Asbestos_Exposuret.pdf ].
 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, ROSATO 1959, 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 Copy on file as 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
Basic Information about Asbestos, US EPA, web search 08/17/2010, original source: http://www.epa.gov/asbestos/pubs/help.html
"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
Copy on file as 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
[copy on file as /hazmat/Vermiculite_US_EPA.pdf/ Current Best Practices for Vermiculite Attic Insulation - May 2003, U.S. EPA
[copy on file as] /hazmat/Vermiculite_Health_Canada.pdf] Vermiculite Insulation Containing Amphibole Asbestos - September 2009, Health Canada
Managing Asbestos in Place, How to Develop and Maintain a Building Asbestos Operations and Maintenance (O&M) Program, U.S. EPA, web search 01/20/2011, original source: http://www.epa.gov/asbestos/pubs/management_in_place.html
Asbestos Strategies, Lessons Learned about Management and Use of Asbestos: Report of Findings and Recommendations on the Use and Management of Asbestos, 16 May 2003, US EPA, web search 01/20/2011, original source: http://www.epa.gov/asbestos/pubs/asbstrategiesrptgetf.pdf
prepared by the: Global Environment & Technology Foundation, 7010 Little River Turnpike, Suite. 460, Annandale VA 20003
Other US EPA Publications on asbestos: web search 01/20/2011, see http://www.epa.gov/asbestos/pubs/pubs.html
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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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.
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