TYPES OF INSULATION
The following general designations are generic names of the materials. The individual manufacturers have different trade names for each of them. For each of the separate types, various properties will be compared, with the following properties common to all.
1. They must have been tested for fire-related values by the ASTM, NFPA, and UL as previously discussed, and meet the minimum standard for a flame spread of 25 and smoke-developed rating of 50 or less except where otherwise noted.
2. The temperature at which the k and R figures have been calculated is 75F (24C).
The following general designations are generic names of the materials. The individual manufacturers have different trade names for each of them. For each of the separate types, various properties will be compared, with the following properties common to all.
1. They must have been tested for fire-related values by the ASTM, NFPA, and UL as previously discussed, and meet the minimum standard for a flame spread of 25 and smoke-developed rating of 50 or less except where otherwise noted.
2. The temperature at which the k and R figures have been calculated is 75F (24C).
Fiberglass
Fiberglass insulation (ASTM C 547) is fibrous glass, made either plain or with a heat-resistant binder in order for the fiberglass to hold its shape. Typical values for material with a density of 3 to 5 lb/ ft3 (48 to 80 kg/m3) are k 0.22 to 0.26 and R 3.8 to 4.5.
Fiberglass is the most popular insulation, and it comes in many forms. Felted glass fiber without any binder is available in rolls. Made with a thermosetting resin binder, it comes in several different stiffnesses. In the form most commonly used for pipe, it is molded and shaped into semicircular sections. The binder is the critical factor for the ultimate temperature for which it can be used.
Cellular Glass
Cellular glass insulation (ASTM C 552) is pure glass with closed cell air spaces. This material has a flame spread of 5 and smoke developed of 0. It also has a 0 perm rating. The typical k value is 0.38 and the R value is 2.6. A jacket is necessary for abrasion resistance; the type used depends upon the expected severity of service.
Fiberglass insulation (ASTM C 547) is fibrous glass, made either plain or with a heat-resistant binder in order for the fiberglass to hold its shape. Typical values for material with a density of 3 to 5 lb/ ft3 (48 to 80 kg/m3) are k 0.22 to 0.26 and R 3.8 to 4.5.
Fiberglass is the most popular insulation, and it comes in many forms. Felted glass fiber without any binder is available in rolls. Made with a thermosetting resin binder, it comes in several different stiffnesses. In the form most commonly used for pipe, it is molded and shaped into semicircular sections. The binder is the critical factor for the ultimate temperature for which it can be used.
Cellular Glass
Cellular glass insulation (ASTM C 552) is pure glass with closed cell air spaces. This material has a flame spread of 5 and smoke developed of 0. It also has a 0 perm rating. The typical k value is 0.38 and the R value is 2.6. A jacket is necessary for abrasion resistance; the type used depends upon the expected severity of service.
Cellular glass is used where an extremely strong and impermeable material is required. It is also impervious to common acids and corrosive environments, and must be cut with a saw. It is available either plain or with a variety of factory-applied jackets.
Expanded Plastic Foam
Elastomeric plastic insulation (ASTM C 534) is an expanded foam, closed cell material, made from nitrile rubber and polyvinyl chloride resin. The typical k value is 0.27 and the R value is 3.6. This material has a perm rating of only 0.17, and does not require a jacket except for appearance; it can also be painted. The flame ratings of 50 are valid for all thicknesses. For material 1⁄2 in (15 mm) thick and less, a smoke-developed rating of 100 has been established; up to 1 in (25 mm), the rating is close to 150. Because of the high rating, building codes do not allow
it to be used in all types of construction. A recent development has enabled manufacturers to reduce the smoke-developed rating down to 50 or below.
Recommended applications for pipes include temperatures from 35 to 220F (1.5 to 103C), and for sheets up to 180F (81C), due to the adhesive required to apply it to a tank. It is used in pipe spaces and boiler and mechanical equipment rooms, where code requirements may be relaxed and the ease of application could make it more cost effective.
Elastomeric plastic insulation (ASTM C 534) is an expanded foam, closed cell material, made from nitrile rubber and polyvinyl chloride resin. The typical k value is 0.27 and the R value is 3.6. This material has a perm rating of only 0.17, and does not require a jacket except for appearance; it can also be painted. The flame ratings of 50 are valid for all thicknesses. For material 1⁄2 in (15 mm) thick and less, a smoke-developed rating of 100 has been established; up to 1 in (25 mm), the rating is close to 150. Because of the high rating, building codes do not allow
it to be used in all types of construction. A recent development has enabled manufacturers to reduce the smoke-developed rating down to 50 or below.
Recommended applications for pipes include temperatures from 35 to 220F (1.5 to 103C), and for sheets up to 180F (81C), due to the adhesive required to apply it to a tank. It is used in pipe spaces and boiler and mechanical equipment rooms, where code requirements may be relaxed and the ease of application could make it more cost effective.
Foamed Plastic
Foamed plastic insulation is a continuously molded, rigid product made from foaming plastic resin, which results in a closed cell material. Typical insulation materials are polyurethane (ASTM C 591), polystyrene (ASTM C 578), and polyethylene. A factory-applied jacket is usually provided. The typical k value is 0.15; R value is 6.7.
Due to the possibly wide variations in the composition of the materials that fall into this category of insulation, the fire rating varies between manufacturers. Although the materials are combustible, they can be made self-extinguishing. Foamed plastic is recommended for low temperatures including cryogenic, and for moderate temperatures, generally up to a maximum of about 220F (103C).
Foamed plastic insulation is a continuously molded, rigid product made from foaming plastic resin, which results in a closed cell material. Typical insulation materials are polyurethane (ASTM C 591), polystyrene (ASTM C 578), and polyethylene. A factory-applied jacket is usually provided. The typical k value is 0.15; R value is 6.7.
Due to the possibly wide variations in the composition of the materials that fall into this category of insulation, the fire rating varies between manufacturers. Although the materials are combustible, they can be made self-extinguishing. Foamed plastic is recommended for low temperatures including cryogenic, and for moderate temperatures, generally up to a maximum of about 220F (103C).
Calcium Silicate
Calcium silicate (ASTM C 533) insulation is a rigid material compounded from silica, asbestos-free reinforcing fibers, and lime. At 500F (260C), it has a k value of 0.5 and an R value of 2.0. A field-applied jacket is required. This insulation is commonly referred to as ‘‘calsil.’’
Mineral Fiber
Mineral fiber (ASTM C 553) insulation is a rigid material composed of rock and slag made into fibers bound together with a heat-resistant inorganic binder. The typical k value is 0.28, and the R value is 4.9. This material is very well suited for high temperature work.
Mineral fiber (ASTM C 553) insulation is a rigid material composed of rock and slag made into fibers bound together with a heat-resistant inorganic binder. The typical k value is 0.28, and the R value is 4.9. This material is very well suited for high temperature work.
Insulating Cement
Insulating cement is produced from fibrous and/or granular insulation and cement, then mixed with water to form a plastic mass. Typical k values range between 0.65 and 0.95, depending upon the composition of the cement. They can be of either the hydraulic setting or the air drying type. This material is best suited for irregular surfaces or as a finish for other insulation applications. It can also be used in situations where space is at a premium and some kind of insulation is required. Installation costs are very high.
Insulating cement is produced from fibrous and/or granular insulation and cement, then mixed with water to form a plastic mass. Typical k values range between 0.65 and 0.95, depending upon the composition of the cement. They can be of either the hydraulic setting or the air drying type. This material is best suited for irregular surfaces or as a finish for other insulation applications. It can also be used in situations where space is at a premium and some kind of insulation is required. Installation costs are very high.
JACKETS
In order to function more efficiently and extend service life, most insulation must be protected from damage and degradation by the application of an effective cover, or jacket material. A jacket is defined as any material, except cements and paints, that can be used to cover or protect insulation installed on a pipe or vessel. The choice of jacketing will depend upon its use, which can be divided into seven general functional categories:
1. Weather barriers are used to prevent the entry of liquid water into insulation and also the entry of chemicals that would affect the inside or outside of the insulation. Materials include plastic, aluminum, and stainless steel as well as weather barrier mastics.
2. Vapor barriers are used to reduce the entry of water vapor into the surface of the insulation. In order to be effective, the vapor barrier must be completely sealed at every opening. A vapor barrier is used on cold surfaces primarily for eliminating the possibility of entrapped water vapor condensing on the pipe.
3. Mechanical abuse-resistant coverings are used to protect the underlying insulation from mechanical damage due to abuse or accidental contact by personnel or equipment. The compressive strength of the insulation used should be considered when selecting a jacket. Metal products are most commonly used.
4. Corrosion- and fire-resistant coverings are used as part of a complete hazard resistance system. Almost any type of jacket or mastic increases the fire rating. The most successful corrosion jackets are plastic or stainless steel depending upon the nature of the spill, leak, or atmosphere expected. Some mastics are also useful.
5. The visual appearance of some jackets over piping in exposed areas is an important feature in the selection of various coatings, finishes, cements, and covers. Since this consideration must often be approved by an architect or client, he or she should be consulted before final selection.
6. Jackets capable of being disinfected are used to present a smooth surface that will resist fungal and bacterial growth. They must withstand cleaning with powerful detergents coupled with steam and high pressure water. This requires a jacket with high mechanical strength.
7. Plain jackets are used on hot services and in other cases when a jacket is desired
for ease of installation and appearance. Jackets come in various forms and types, and can be divided into three general categories: rigid (plastic, aluminum, or stainless steel), membrane (glass cloth, coated papers, treated papers, and papers laminated with foils and/or cloth), and mastic. Jackets can be specified separately or factory applied. Separate jackets are used for special situations when a factory applied jacket is not available or possible, for example, jackets made of aluminum or plastic sheets. The factory applied jacket is by far the most common and is available in three types: the so-called all-purpose jacket, which has a vapor barrier, a plain jacket, and a weatherproof jacket.
Each manufacturer has a different combination of materials that are laminated to each other to provide flexibility, strength, and fire resistance. Kraft paper that has been coated or treated with chemicals is the most common base. The next layer is usually fiberglass cloth, used for strength, and the third layer is usually an aluminum foil. All three layers are permanently bonded together with a special adhesive to give the desired strength and water vapor retardation characteristics.
All-Service Jacket (ASJ)
The all-purpose, or all-service, jacket has a vapor barrier. The complete jacket is a lamination of kraft paper, fiberglass cloth (skrim) and either aluminum foil or metalized film. This is commonly referred to as an FSK jacket, for foil, skrim, and kraft. The kraft paper is a bleached 30-lb (13.5 kg) basis weight material, which means 30 lb (13.5 kg) for each 30,000 ft2 (2790 m2) area (or one ream). There is also a 45-lb (20.2 kg) basis weight paper available if a heavier paper is desired. The fiberglass scrim is used for strength and reinforcement of the paper. The standard weave is 5 5, which means five lines per inch. Other weaves are available, ranging from 1 1 to 10 10, and also a 10 20. Also available is a bias weave, which adds diagonal threads in a third direction. The closer the weave, the stronger the jacket.
The foil used is aluminum, ranging in thickness from 0.35 to 1.0 mil. The standard thickness is 0.50 mil. Metalized film is also available. Although thinner than foil, it retains its shape better under impact. One manufacturer described its product as a white, metalized polypropylene film with a perm rating of 0.02.
The composition of the adhesive and the actual methods used to bind the components together are proprietary. It is the adhesive that imparts the fire resistant rating to the entire jacket system. After a layer of adhesive is applied to the kraft paper, the scrim is added and the adhesive forced through the weave. Finally, the foil or metalized film is put on next. The three layers are then laminated together to form the complete jacket system.
Lagging
Lagging is the process of insulating a pipe or vessel and then covering the insulation with a cloth jacket. The jacket is primarily used to improve the surface appearance of any insulation, offering very little in the way of protection. Lagging materials are available in a full spectrum of colors and may eliminate the need for painting. This cloth can be canvas or fiberglass, for example, and is secured to the insulation with lagging adhesive and/or sizing. Also available is a combination system that serves as both an adhesive and protective coat.
Aluminum Jackets
Aluminum jackets (ASTM B-209) are available in a corrugated or smooth shape and in thicknesses ranging from 0.010 to 0.024 in, with 0.016 in being the most commonly used. Also available are different tempers or hardness. These range from H 14 (half hard) to H 19 (full hard), with H 14 being the most common. Aluminum jackets can be secured by one of three different methods: banded by straps on 9-in centers, by a patented seam in an S or Z configuration, or by sheet metal screws. The ends are overlapped 2 in and secured with straps or screws (or nothing for the interlocking type). Since they are usually applied over insulation, a variety of vapor barrier materials can be factory applied to the aluminum jackets, which may be necessary if the insulation has any ingredient that causes galvanic or corrosive attack on the aluminum, or if an additional vapor barrier is thought to be necessary. Fittings are fabricated from roll material in the shop. There are four different alloys of aluminum commonly used for jacketing material: 1100, 3003, 3105, and 5005. Although there are differences among them, it is not usually necessary to specify which alloy is to be used. The properties of all types are so closely matched that the service or performance of the material is not affected by different choices. It is common practice for the fabricator of the jacket to interchange any of the four types depending upon availability and price. By specifying the ASTM code alone, the engineer is allowing the contractor to use any of the types (since they are all acceptable), and avoids the possibility of a delay caused by waiting for the particular alloy specified and the extra cost involved.
One alloy, 1100, is mostly used for fittings because it is the most malleable of the four. If the jacketing is used on a pipe that may expand and contract often because of system operation, corrugated aluminum jackets should be used. These jackets easily expand and contract. Aluminum jackets have the following advantages:
1. Easy application in any weather
2. Easy formation into different shapes
3. Good resistance to abuse
4. Ready availability
In order to function more efficiently and extend service life, most insulation must be protected from damage and degradation by the application of an effective cover, or jacket material. A jacket is defined as any material, except cements and paints, that can be used to cover or protect insulation installed on a pipe or vessel. The choice of jacketing will depend upon its use, which can be divided into seven general functional categories:
1. Weather barriers are used to prevent the entry of liquid water into insulation and also the entry of chemicals that would affect the inside or outside of the insulation. Materials include plastic, aluminum, and stainless steel as well as weather barrier mastics.
2. Vapor barriers are used to reduce the entry of water vapor into the surface of the insulation. In order to be effective, the vapor barrier must be completely sealed at every opening. A vapor barrier is used on cold surfaces primarily for eliminating the possibility of entrapped water vapor condensing on the pipe.
3. Mechanical abuse-resistant coverings are used to protect the underlying insulation from mechanical damage due to abuse or accidental contact by personnel or equipment. The compressive strength of the insulation used should be considered when selecting a jacket. Metal products are most commonly used.
4. Corrosion- and fire-resistant coverings are used as part of a complete hazard resistance system. Almost any type of jacket or mastic increases the fire rating. The most successful corrosion jackets are plastic or stainless steel depending upon the nature of the spill, leak, or atmosphere expected. Some mastics are also useful.
5. The visual appearance of some jackets over piping in exposed areas is an important feature in the selection of various coatings, finishes, cements, and covers. Since this consideration must often be approved by an architect or client, he or she should be consulted before final selection.
6. Jackets capable of being disinfected are used to present a smooth surface that will resist fungal and bacterial growth. They must withstand cleaning with powerful detergents coupled with steam and high pressure water. This requires a jacket with high mechanical strength.
7. Plain jackets are used on hot services and in other cases when a jacket is desired
for ease of installation and appearance. Jackets come in various forms and types, and can be divided into three general categories: rigid (plastic, aluminum, or stainless steel), membrane (glass cloth, coated papers, treated papers, and papers laminated with foils and/or cloth), and mastic. Jackets can be specified separately or factory applied. Separate jackets are used for special situations when a factory applied jacket is not available or possible, for example, jackets made of aluminum or plastic sheets. The factory applied jacket is by far the most common and is available in three types: the so-called all-purpose jacket, which has a vapor barrier, a plain jacket, and a weatherproof jacket.
Each manufacturer has a different combination of materials that are laminated to each other to provide flexibility, strength, and fire resistance. Kraft paper that has been coated or treated with chemicals is the most common base. The next layer is usually fiberglass cloth, used for strength, and the third layer is usually an aluminum foil. All three layers are permanently bonded together with a special adhesive to give the desired strength and water vapor retardation characteristics.
All-Service Jacket (ASJ)
The all-purpose, or all-service, jacket has a vapor barrier. The complete jacket is a lamination of kraft paper, fiberglass cloth (skrim) and either aluminum foil or metalized film. This is commonly referred to as an FSK jacket, for foil, skrim, and kraft. The kraft paper is a bleached 30-lb (13.5 kg) basis weight material, which means 30 lb (13.5 kg) for each 30,000 ft2 (2790 m2) area (or one ream). There is also a 45-lb (20.2 kg) basis weight paper available if a heavier paper is desired. The fiberglass scrim is used for strength and reinforcement of the paper. The standard weave is 5 5, which means five lines per inch. Other weaves are available, ranging from 1 1 to 10 10, and also a 10 20. Also available is a bias weave, which adds diagonal threads in a third direction. The closer the weave, the stronger the jacket.
The foil used is aluminum, ranging in thickness from 0.35 to 1.0 mil. The standard thickness is 0.50 mil. Metalized film is also available. Although thinner than foil, it retains its shape better under impact. One manufacturer described its product as a white, metalized polypropylene film with a perm rating of 0.02.
The composition of the adhesive and the actual methods used to bind the components together are proprietary. It is the adhesive that imparts the fire resistant rating to the entire jacket system. After a layer of adhesive is applied to the kraft paper, the scrim is added and the adhesive forced through the weave. Finally, the foil or metalized film is put on next. The three layers are then laminated together to form the complete jacket system.
Lagging
Lagging is the process of insulating a pipe or vessel and then covering the insulation with a cloth jacket. The jacket is primarily used to improve the surface appearance of any insulation, offering very little in the way of protection. Lagging materials are available in a full spectrum of colors and may eliminate the need for painting. This cloth can be canvas or fiberglass, for example, and is secured to the insulation with lagging adhesive and/or sizing. Also available is a combination system that serves as both an adhesive and protective coat.
Aluminum Jackets
Aluminum jackets (ASTM B-209) are available in a corrugated or smooth shape and in thicknesses ranging from 0.010 to 0.024 in, with 0.016 in being the most commonly used. Also available are different tempers or hardness. These range from H 14 (half hard) to H 19 (full hard), with H 14 being the most common. Aluminum jackets can be secured by one of three different methods: banded by straps on 9-in centers, by a patented seam in an S or Z configuration, or by sheet metal screws. The ends are overlapped 2 in and secured with straps or screws (or nothing for the interlocking type). Since they are usually applied over insulation, a variety of vapor barrier materials can be factory applied to the aluminum jackets, which may be necessary if the insulation has any ingredient that causes galvanic or corrosive attack on the aluminum, or if an additional vapor barrier is thought to be necessary. Fittings are fabricated from roll material in the shop. There are four different alloys of aluminum commonly used for jacketing material: 1100, 3003, 3105, and 5005. Although there are differences among them, it is not usually necessary to specify which alloy is to be used. The properties of all types are so closely matched that the service or performance of the material is not affected by different choices. It is common practice for the fabricator of the jacket to interchange any of the four types depending upon availability and price. By specifying the ASTM code alone, the engineer is allowing the contractor to use any of the types (since they are all acceptable), and avoids the possibility of a delay caused by waiting for the particular alloy specified and the extra cost involved.
One alloy, 1100, is mostly used for fittings because it is the most malleable of the four. If the jacketing is used on a pipe that may expand and contract often because of system operation, corrugated aluminum jackets should be used. These jackets easily expand and contract. Aluminum jackets have the following advantages:
1. Easy application in any weather
2. Easy formation into different shapes
3. Good resistance to abuse
4. Ready availability
Aluminum jackets have the following disadvantages:
1. Low resistance to pH ranging from 7 to 11
2. Low fire rating
3. Low emittance value
4. High initial cost
5. Low resistance to strong cleaning chemicals
Stainless Steel Jackets
Stainless steel jackets (ASTM A-240) are available in either flat or corrugated forms and in standard thicknesses of 0.010, 0.016, and 0.019. They are secured in the same manner as aluminum jackets. A factory applied moisture barrier can also be added.
The most commonly available alloys are types 301, 302, 303, 304, 305, and 316; 304 is the most popular. It is best to consult with the manufacturer for the criteria that will help determine which alloy would be best for any particular application. Several types of finishes are available, from polished to dull. Stainless steel jackets have the following advantages:
1. Excellent fire rating
2. High resistance to mechanical abuse
3. Excellent corrosion and weather resistance
4. Easy application in any weather
5. Excellent hygienic characteristics
Stainless steel jackets (ASTM A-240) are available in either flat or corrugated forms and in standard thicknesses of 0.010, 0.016, and 0.019. They are secured in the same manner as aluminum jackets. A factory applied moisture barrier can also be added.
The most commonly available alloys are types 301, 302, 303, 304, 305, and 316; 304 is the most popular. It is best to consult with the manufacturer for the criteria that will help determine which alloy would be best for any particular application. Several types of finishes are available, from polished to dull. Stainless steel jackets have the following advantages:
1. Excellent fire rating
2. High resistance to mechanical abuse
3. Excellent corrosion and weather resistance
4. Easy application in any weather
5. Excellent hygienic characteristics
Stainless steel jackets have the following disadvantages:
1. High initial cost
2. Corrosion cracking where chlorine or fluorine exists
3. Low emittance value
4. Long lead time
There are often strict union regulations requiring that stainless steel jackets over 0.20 in thick be installed by sheet metal workers. Jackets 0.20 in thick or less can be installed by the insulation contractor. The insulation contractor is more knowledgeable about this kind of work, so when job conditions permit, it is usually more cost effective to specify the thinner thickness to ensure that the work will be done by the insulation contractor.
Wire Mesh
Wire mesh is a little-known jacket material. It’s mainly used when a strong, flexible, abrasion-resistant covering that must be easily removed is needed. It is available in widths from 1 to 43 in (25 to 1075 mm), with 12, 18, 24, and 30 in (300, 450, 600, and 750 mm) used most often. Common wire diameter of the mesh is either 0.008 or 0.011 in. The thicker wire is used where greater strength is needed or heavy use expected. The openness of the weave is expressed in density, which gives the number of openings per inch. Densities of 48 to 130 are used, with 60 being the most common. Material of the mesh can be Monel, Inconel, or stainless steel. It is attached with lacing hooks or sewn with stainless steel wire. In addition, it must be secured with either tie wires or metal straps.
Plastic Jackets
Plastic jackets are manufactured in a great variety of materials, including PVC, ABS, PVF, PVA, and acrylics. Thickness ranges from 3 to 35 mils. The manufacturers should be consulted to determine the criteria necessary to select the best material and thickness for any particular application. Plastic jackets have the following advantages:
1. Lowest cost of any solid jacket
2. Best resistance to chemical corrosion
3. Excellent resistance to bacterial and fungal growth
Plastic jackets have the following disadvantages:
1. Poor fire rating
2. Low impact resistance
3. Softening at high temperatures
4. Vulnerability to infrared and ultraviolet rays and ozone
5. Cold weather embrittlement
1 comment:
nice posting bror... but will better if you make a summary about it. long explanation in posting make borring. please add with cryogenic insullation...
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