1. PURPOSE
1.1 This fabrication and erection specification defines the minimum requirements for removable insulation covers for use on valves, flanges (with limitations), equipment, and instrumentation.
2. scope
2.1 This specification defines the types and quality of materials, the hardware, and the construction methods for removable insulation covers.
2.2 These covers will be utilized for valves, expansion joints, equipment, and instrumentation requiring periodic access for maintenance or inspection with component operating temperatures from +100 to +1200F. These covers will also be utilized for flanges and for vessel manway covers with operating temperatures from +100° to +800°F, maximum.
3. related documents
3.1 U.S. Department of Defense (DOD) MIL-I-24244 Insulation Materials with Special Corrosion, Chloride, & Fluoride Requirements MIL-I-16411 Insulation Felt, Thermal, Glass Fiber MIL-C-20079 Cloth, Glass; Tape, Textile Glass; and Thread, Glass and Wire-Reinforced Glass
4. REQUIREMENTS
4.1 The fabrication of these removable insulation covers shall be performed in strict accordance with this specification as well as any individual specification indicated in the project-specific documents.
4.2 Before the removable covers are installed, all surfaces shall be cleaned of dirt, rust, and any other foreign matter. In addition, when corrosion protection is required for surfaces under the insulation, as indicated on the project’s Painting Schedule, then the surface protection shall be installed prior to the installation of any covers.
4.3 Each cover shall have a close contour fit for a neat appearance and proper thermal performance. Overlapping seams and air gaps are not acceptable. Force folding or crimping of the cover is not acceptable and shall not be performed during fabrication.
4.4 Multiple-piece construction is acceptable.
4.5 In the quotation submitted by the contractor, the contractor shall furnish for Air Products’ approval, the fabricator, material, and model number of all removable insulation covers to be supplied. For noise attenuation covers, the submittal shall include the acoustic performance of the covers.
5. MATERIALS
5.1 The materials specified in Section 10 of this specification shall be used in the fabrication of removable insulation covers.
5.2 The total thickness of each removable insulation cover shall be at least the same thickness as required on the adjacent pipe.
5.3 Insulation thicknesses are normally indicated on the project-specific documents. Those not listed and those requiring special process considerations shall be determined on a case-by-case basis by consultation with the Air Products representative.
6. CONSTRUCTION DETAILS
6.1 Covers shall be constructed and installed to shed water. The closing seams shall be located at the gravitational bottom.
6.2 Covers shall overlap adjacent pipe insulation by a minimum of 2 inches.
6.3 Individual covers or pieces thereof shall not weigh more than 65 pounds.
6.4 All cloth seams shall be sewn using a lock stitch or a double stitching method with a minimum of seven stitches per inch. The thread shall be able to withstand the full process temperature without degradation. Suitable thread materials are specified in paragraph 10.3.
6.5 Hog rings or staples shall not be used as a method of cloth seam closure. However, they may be used to join stainless steel mesh seams.
6.6 All jacket edges shall be covered with a trifold of cloth material to encase the jacket edge. Cut jacket edges shall not be exposed to the elements.
6.7 Insulation within the jacket shall be mechanically fastened in-place to prevent shifting using through-cover quilting pins located on 12-inch centers.
6.8 The following fastening techniques are acceptable and shall be used for holding the cover correctly in place:
6.8.1 Cinch belts shall be made of outer jacket material or fiberglass, 1-inch wide web belting with two stainless steel O-ring fasteners. All belt edges shall be double folded and double stitched. Belt loops shall be provided on the outer jacket to hold belts in place.
6.8.2 The stainless steel lacing anchors shall be firmly attached to the outer jacket at least 2 inches from the edge and spaced a maximum of 8 inches on center. Stainless steel lacing wire, Type 304, annealed, 18-to-20 gauge shall be used to draw the insulation seams together. The contractor shall use as many anchors as are necessary to ensure that the insulation is adequately secured.
6.9 Valve covers shall be fabricated to slip over valves from the top or from the side and shall enclose the valve flanges and valve bonnet. Valve covers that wrap around the valve from the bottom and fasten at the top are not acceptable, unless the top joint is covered with a wind/rain flap 6 inches long.
6.10 With the exception of the parting line, all ends of covers with openings for protrusions shall utilize windflaps to repel moisture and prevent excessive convective heat loss. The windflap cuff shall be fabricated from the cold face fabric. Nomex drawstrings shall be machine stitched at the middle of the windflap cuff to prevent the drawstring from being pulled out.
7. MATERIALS OF CONSTRUCTION
7.1 The removable insulation covers for normal use shall be made of the materials specified in Table 1. The removable insulation covers for noise attenuation shall be made of the materials specified in Table 2. The piping and/or equipment service temperature is the governing criteria for the removable cover design.
8. IDENTIFICATION TAG
8.1 Each removable insulation cover or piece thereof shall have an identification tag firmly attached to the outer jacket.
8.2 The tag shall be a minimum of 2 x 4 inches and made of copper-free aluminum or stainless steel.
8.3 Each tag shall contain the fabricator’s name. The identification or tag number of the item to be covered shall be etched or stamped on the tag.
9. ACCEPTABLE SUPPLIERS
9.1 The following manufacturers are acceptable suppliers of prefabricated and custom fabricated insulation covers: Advance Thermal Corp. Bensenville, IL Brandywine Insulation Corporation Chester Heights, PA Multiglas Products Company Buffalo, NY PACOR, Inc. Westville, NJ Shannon Enterprises North Tonawanda, NY
10. MATERIAL SPECIFICATIONS
10.1 Jacket Material
10.1.1 J-1 Untreated woven fiberglass: Fiberglass fabric (de fiber), 17.8 ounces per square yard, maximum service temperature shall be 1000F, shall meet DOD MIL-C-20079, Type I, Class 9 and MIL-1-24244. Acceptable suppliers and materials are:
| Alpha Associates, Incorporated | 2025/9383 |
| Woodbridge, NJ | |
| The Claremont Sales Corporation | 1925/A557 |
| Meriden, CT | |
| Clark-Schwebel, Inc. | 2025/9383 |
| Anderson, SC | |
| JPS Glass Fabrics | 2025/9383 |
| Slater, SC |
10.1.2 J-2 Silicone impregnated fiberglass, Type 1: Silicone-coated, satin weave fiberglass fabric meeting DOD MIL-C-20079, Type I, Class 9 and MIL-1-24244. Specially formulated flame-retardant silicone rubber shall be 25% of the total weight of the fabric, 16 ounces per square yard and 0.017 inch thick, minimum. Maximum continuous service temperature shall be 500F. Acceptable suppliers and materials are:
| Alpha Associates, Incorporated | 3259-2-SS |
| Woodbridge, NJ | |
| 3M Company | SRG 11717 |
| St. Paul, MN |
10.1.3 J-3 Stainless steel wire mesh: Knitted Type 304 stainless steel wire mesh; wire thickness shall be 0.011 inch with a 60 density mesh size. Maximum continuous service temperature shall be 1200F. Acceptable suppliers and materials are:
| ACS Industries, Inc. | See Specification |
| Woonsocket, RI | |
| Alpha Associates, Incorporated | 91160 |
| Woodbridge, NJ | |
| Metex Corporation | See Specification |
| Edison, NJ |
10.2 Insulation Material
10.2.1 T-1 Fiberglass mat: Thermal insulation shall be composed of 100% Type E needled glass fiber. Density of the mat shall be 10 pounds per cubic foot (pcf), minimum. The glass mat shall not contain any binders and shall be suitable for temperatures up to 1200F. Alkalinity shall be 0.15% or less. Thermal conductivity shall not exceed 0.45 Btu-inches/ft2 per hour F at a mean temperature of 400F. The insulation shall comply to DOD MIL-1-16411, Type II and MIL-1-24244. Acceptable suppliers and materials are:
| BGF Industries, Inc. | Burlglass |
| Greensboro, NC | 1200 |
| JPS Glass Fabrics | Insulbatte |
| Slater, SC | 1031 |
| PACOR, Inc. | Pacomat |
| Westville, NJ |
10.2.2 T-2 Ceramic insulation: Ceramic fiber blanket shall be manufactured from inorganic, fibrous materials of uniform density using the hot needled method of fabrication. Materials containing binders, fillers, fibers, oils, or other substances which will burn, melt, vaporize, or carbonize at 1200F or less are not acceptable. Ceramic materials shall have an alkalinity of 0.8% or less and shall contain not more than 10 ppm of leachable chlorides. Density of the blanket shall be 5.5 pcf, minimum. Thermal conductivity shall not exceed 0.42 Btu-inches/ft2 per hour F at a mean temperature of 400F. Maximum continuous service temperatures shall be 1200F. Acceptable suppliers and materials are:
| Premier Refractories and Chemicals, Inc. | CER-WOOL |
| King of Prussia, PA |
| Thermal Ceramics | Kaowool |
| Augusta, GA | Needled Blanket |
| Unifrax Corp. | Fiberfrax |
| Niagara Falls, NY | Needled Blanket |
10.3 Sewing Thread Material
10.3.1 S-1 Sewing thread, 100F to 1200F: This thread shall be 0.021 inch diameter made of Teflon-coated fiberglass. It shall have four strands and have a minimum 18 pound tensile strength. Acceptable suppliers and materials are:
| Alpha Associates, Incorporated | D-24 |
| Woodbridge, NJ | |
| Synthetic Thread Company, Incorporated | E-18 |
| Bethlehem, PA |
| Saunders Thread Company | E-18 |
| Gastonia, NC |
10.4 Insulation for Noise Attenuation
10.4.1 N-1 Prefabricated insulation system for noise attenuation – Up to 450F: This prefabricated insulation system shall consist of a Teflon-coated, fiberglass cloth jacket, a single layer of Type E needled fiberglass insulation, and a sound-insulating blanket laced together using Type 304 stainless steel, 18-gauge wire stitching. Jacketing shall possess a weight of 16 ounces per square yard and have a minimum thickness of 0.017 inch. This insulation shall have a maximum continuous service temperature of 450F. Insulation shall be asbestos-free, 10-pcf minimum density, Type E needled fiberglass with a 0.125 inch thick, one-pound-per-square-foot, nonreinforced, barium sulfate-loaded vinyl located on the cold-face of the sound-insulating blanket. A maximum thermal conductivity of 0.50 Btu-inches/ft2 per hour F at a mean temperature of 500F shall not be exceeded. Acceptable suppliers and materials are:
| BRD Noise & Vibration Control | HUSHCOVER |
| Wind Gap, PA | Model BRD-450 |
| Shannon Enterprises | Custom design |
| North Tonawanda, NY |
10.4.2 N-2 Prefabricated insulation system for noise attenuation – Up to 800F: This prefabricated insulation system shall consist of a plain fiberglass cloth, hot-faced jacket, a stainless steel enclosure mesh, a single layer of Type E needled fiberglass insulation, a sound-insulating blanket, and a Teflon-coated, fiberglass cloth, cold-faced jacket laced together using Type 304 stainless steel, 18‑gauge wire stitching. Hot-faced jacketing shall be plain fiberglass cloth and possess a weight of 16 ounces per square yard (minimum) with a Type 304 stainless steel enclosure mesh diameter of 0.011 inch. Hot-faced jacket insulation shall have a maximum continuous service temperature of 800F. Insulation shall be the same as that in N-1. Cold-faced jacketing shall possess a weight of 16 ounces per square yard and have a minimum thickness of 0.017 inch. Cold-faced jacket insulation shall have a maximum continuous service temperature of 450F. Acceptable suppliers and materials are:
| BRD Noise & Vibration Control | HUSHCOVER |
| Wind Gap, PA | Model BRD-800 |
| Shannon Enterprises | Custom design |
| North Tonawanda, NY |
10.4.3 Supplier shall submit the certified acoustic performance of the actual product(s) to be provided prior to the fabrication of any covers.
10.4.4 When project-specific noise attenuation requirements cannot be met using a single layer cover, multiple layers of covers maybe installed. Each layer shall be fabricated totally independent of the other and shall be installed such that the layers are mechanically decoupled. The supplier shall provide certified acoustic performance data for the multiple layer installation.
Table 1 Materials of Construction for Normal Use
| Service Temperature | Layer | Material of Construction |
| +100 to +1000F | Outer Jacket | J-2 |
| Insulation | T-1 or T-2 | |
| Inner Jacket | J-1 or J-3 | |
| Sewing Thread | S-1 | |
| +1001 to +1200F | Outer Jacket | J-2 |
| Insulation | T-1 or T-2 | |
| Inner Jacket | J-3 | |
| Sewing Thread | S-1 |
Table 2 Materials of Construction for Sound Attenuation
| Service Temperature | Layer | Material of Construction |
| Ambient to +450F | Prefabricated System | N-1 |
| +451 to +800F | Prefabricated System | N-2 |