This method statement covers the general requirements for materials and application of external thermal insulation on the hot surfaces of piping and equipment’s as applicable on the project or facilities i.e. boilers, refineries etc.
The external surface of equipment, piping and machinery shall be insulated to conserve energy by reducing heat loss and to facilitate temperature and sound control of process system.
- Equipment and piping shall be insulated under the following conditions:
- Hot insulation for the surface having temperature above 60 degree Celsius
Personal Protection Insulation to protect operators
Personnel protection shall be provided for operating equipment, piping and machinery when the surface temperature is more than 60o On the condition that the items to be protected are located in the area not exceeding 2.13 meters above operating floor and not more than 0.91 meters away from the access side and as instructed by site in-charge.
For personnel protection at vertical pipe, a watertight metallic termination cover shall be provided with tapered to shed water.
Removable type insulation shall be used in areas where access for frequent maintenance is necessary. The insulation shall be bonded to the removable cover.
Insulation supports for straight vertical pipes shall be fixed above the bottom elbow and for flanges/valves clearance at a distance of bolt length +25mm.
Contact with dissimilar material, which might cause galvanic corrosion, shall be avoided.
Finished insulation and weatherproofing work shall be installed watertight and shall remain watertight during operation.
Flange and manhole flanges shall not be insulated for equipment’s and lines in Hydrocarbons Services.
Insulation thickness shall be made from thickness tables specified for the job or facility.
Reference Specification:
The following specifications, codes and guides apply for the project with latest revisions as applicable:
- Basic Criteria for Industrial Insulation
- Hot Insulation Installation Details
- Insulation Details for Hot piping
- Hot Service Insulation materials & Installation specifications
- Installation of Hot Service Insulation system
- Installation of Flexible, Removable / Reusable Insulation covers for Hot Insulation Service
If any conflict exists between the requirements of the listed specifications and related codes, data sheets, drawings, requisitions, etc., it should immediately be brought to the attention of the client and an acceptable solution must be reached.
Wherever a difference exists between the method statement & specification the specification shall govern. However, no deviations shall be made from the specification without written authorization from the Client.
MATERIALS
All materials to be used in this project shall be approved by Client. Pre qualification documents shall be submitted to client for approval prior to use.
Materials used in the project should be in accordance with the project specifications.
Contractor’s Quality Inspector and Client nominated representative should carry out an inspection and approve all materials before any job is carried out for the project.
All insulation materials and accessories used for this project shall be delivered to site and contractor shall ensure that all materials are protected from being damaged prior to use.
Only the materials that shall be used in a given workday shall be stored in the immediate work area. All materials shall be stored at designated locations only.
Insulation that becomes wet shall be removed and replaced with dry insulation and wet insulation shall be discarded form the project.
All Insulation materials for Hot Insulation shall be in accordance with the below sections.
Weatherproofing:
All Weatherproofing materials for “Hot Insulation” shall be in accordance with below section of this method statement.
All ancillary materials shall be in accordance with below section of this method statement.
All materials to be used in this project shall be approved by the client prior to start of insulation installation work.
Storage and Handling of Insulation Materials:
Storage of material shall be in accordance with the requirements of the project specification.
All materials shall be stored in a way that it is protected from exposure to weather e.g. rain, dust, etc.
Insulation material shall also be protected from getting wet and getting in contact with chemicals and other flammable substances during storage.
From delivery to the installed finished product, insulation materials shall at all times be protected from the dangerous elements and the storage area shall have adequate drainage.
Insulation materials shall be handled and stored in accordance with the manufacturer’s printed recommendations.
Mastics, adhesives, and sealers that are exposed to temperatures outside the recommended temperature ranges during storage shall be removed from the site and replaced with new material.
Materials that have exceeded shelf life shall be removed from the site and replaced with new material.
Hot Insulation Material Minimum Requirements:
| S. No. | Material Specifications | Material Type |
|
1. |
Pipe Insulation (up to 3” Dia)
ASTM – C547 |
Rock wool pipe section
Nominal Density 100 kg/m3 |
|
2. |
Pipe and Equipment Insulation
ASTM –C592/C612 |
Rock wool Blankets or Slabs/ Boards
Nominal Density 100 kg/m3 |
|
3. |
A). Metal Jacketing
0.5mm thick <= 6” NPS 0.6mm thick >6” up to 20” NPS 0.8mm thick >20” NPS |
Flat aluminium jacketing with moisture barrier
Alloy 3003 with H14 temper ASTM B209 |
| B). Stainless steel jacketing shall be used for Fire hazardous areas. | ||
Note: Materials to complete the above specifications will be from one of the following locations:
- Mineral wool – GCC / Asia /UK
- Aluminum Sheet – GCC / Asia
- Ancillaries – USA / Europe / Asia
FASTENER & ACCESSORY SCHEDULE FOR HOT INSULATION
| Insulated items | Insulation Outside Diameter |
Insulation |
Weatherproofing |
||||
| Fasteners/seals | Max Spacing | Springs | Fasteners | Max Spacing | Springs | ||
| ≤ 300 mm NPS O.D | All sizes | 1.29 mm dia SS304 Wire | 300 mm | N/A | 13X0.5 mm
Band and Wing Seal (SS304) |
300 mm | None |
| >300 mm
≤600 mm NPS/Equipment O.D |
All sizes | 13X0.5 mm
Band and Wing Seal (SS304) |
300 mm | N/A | 13X0.5 mm
Band and Wing Seal (SS304) |
300 mm | None |
| >600 mm NPS/Equipment O.D | All sizes | 19 x 0.5 mm Bands / wing type seal | 300 mm | N/A | 19X0.5 mm
Band and Wing Seal (SS304) |
300 mm | As Applicable |
| SS 304 Screws with Neoprene Washers | All size | N/A | N/A | N/A | 8X13 MM (SS304) | 150 mm | N/A |
| Duct | All sizes | Pin / speed fix washers | 300mm | — | — | — | — |
| Flanges / Valves | All sizes | – | – | – | SS304304
Pop Rivet / Toggle |
As Applicable | N/A |
Silicon Sealant:
| S. No | Joint Sealant | Purpose |
| 1 | Foster 95-44 (Silicone Sealant) | Weatherproofing sealant for cladding joints |
SURFACE PREPARATION
All equipment, vessels, and piping shall have been tested and inspected as required by the relevant specification prior to the installation of hot insulation.
Prior to starting any task a release document will be issued by Quality Controls Inspector and Client nominated representative will check the area or surfaces where Insulation is to be applied and appropriate inspection document will be signed.
Contractor will identify the areas to be insulated by issuing work release document with applicable drawings.
Insulation materials and application shall be in accordance with the project specifications.
All surfaces to be released for insulation shall be dry, clean and free from rust, loose mill scale, grease and dirt.
Insulation material shall be dry on installation and shall be kept free from moisture during and after installation.
Hot Insulation Installation Procedure
Identification of Insulation Requirements:
All application of insulation system shall be in accordance with the Client’s specification and recommendation.
The type and extent of insulation requirements shall be identified in the applicable equipment and isometric drawings.
Personnel protection insulation is specified for surfaces which normally operates continuously at temperature in excess of 60°C but don’t require that heat loss be limited.
Unless otherwise specified, insulation shall be applied only to that portion of the surface subject to contact by an operator in the normal performance of his duties i.e. up to 2.13 Meter above finished grade or platforms and within 0.91 meter horizontally of normal operating locations.
Mineral Wool Pipe Cover shall be used for piping size up to 3”, for pipe sizes over 3” and for equipment Mineral Wool Blanket shall be used unless otherwise specified.
On manholes and hand holes, extent of insulation shall be as follows:
For Hot Equipment, manholes and hand holes shall be thoroughly insulated with removable covers.
Hot Insulation for Equipment
Equipment insulation thickness shall be as indicated on site insulation work list for equipment/isometric drawing.
Application:
The following shall not be insulated for Hot insulation unless otherwise specified:
- Pipe supports and guides
- Inside of skirts on skirt supported towers and vessels 750mm and less in diameter
- Channel covers operating below 93 0C
- Shell and tube heat exchanger flanges
- Steam traps and the outlet side of steam trap piping
- Spectacle blinds
- Drain and vent piping on insulated equipment down stream of the first block valve
- Nameplates
- Untraced branches from traced lines downstream of the first block valve
Insulation on the inside and the outside of support skirt for vertical vessels shall be equal to the shell insulation thickness.
For equipment operating below 400 0C, insulation of the skirt shall extend at least a minimum of four times the shell’s insulation thickness.
On equipment operating above 400 0C, the insulation of skirt shall be 600 mm below tangent line, and to the top of the fireproofing if the skirt is fireproofed.
Insulation material for hot equipment shall be mineral fiber blanket.
All materials approval will be obtained from client prior to the start of the project and the same materials shall be used, however, if any change is required, then the appropriate approval will be obtained as necessary.
The insulation on the shell of equipment below 24 inches shall be secured in place with 13 mm wide 0.5mm thick stainless steel band and seals at a maximum spacing of 300 mm centres unless otherwise noted in the drawings.
The insulation on the equipment 24 inches and over shall be secured in place with 19mm wide 0.5mm thick stainless steel band and seals at a maximum spacing of 300 mm unless otherwise noted in the drawings.
When metal band exceeds 9.1 m between securement points, one breather spring should be provided to accommodate expansion and contraction of the shell.
The mineral wool with density of 100 kg/m3 shall be used as blanket for shell of Vertical equipment and block for top head of vertical equipment.
Banding of insulation over the heads of equipment shall be as follows:
A floating ring, large enough to clear the centre nozzle, if there is any, shall be made from 6 mm diameter carbon steel round bar or from 6 pieces of inter twisted gage #16 SS wire. This ring shall be placed on the centre of the head. A girth ring, made from 2 bands shall be installed on the shell at approximately 150 mm from the tangent line of the head. Bands shall run radially from the floating ring to the girth ring. The radial bands shall be spaced 300 mm maximum centres on the girth ring.
On vertical vessels, which are, skirt supported, the bands on the bottom head shall be attached to the inside skirt support angle or blank nuts.
Stiffener rings shall be insulated with the 50 mm thickness as the same shell insulation materials from the outer exposed surface of the stiffener ring.
Installed insulation shall have the required permanent protection or temporary protection applied before the conclusion of work on that day.
Also the installed insulation shall have temporary protection applied if rain or other forms of atmospheric moisture can damage the insulation during each work shift.
Insulation thicknesses 3-1/2 inch (90mm) and greater shall be applied in multilayers with staggered joints. Consideration shall be given to multilayer insulation for operation temperatures over 600oF (316oC).
Each layer of double layer or multi-layer insulation shall be held in place separately i.e. all layers should be separately secured by using stainless steel wires or bands.
All insulation shall be smooth and free from cracks, voids, gaps and depressions greater than 1/8in. (3mm).
All cracks, voids, gaps and depressions in the insulation greater than 1/8in. (3mm) shall be refitted not filled.
Removable insulation plugs shall be provided to permit on-stream ultrasonic inspection when required by the operating proponent. Plugs shall be vapour tight, ultra violet resistant and be such that they can be opened and reclosed without disturbing the adjacent insulation.
Wicking or fibrous type insulation shall not be used on tanks and vessels handling hydrocarbon liquids with the operating temperature above 93oC where spillage or leakage onto the insulation is likely to occur. Cellular glass insulation shall be used on Tanks and vessels which is impermeable material accordance with ASTM E-96.
Method of Hot Insulation for Piping
Piping Insulation Thickness:
Insulation thickness shall be as indicated on the Piping isometric drawing and Lines list.
For hot and personnel protection insulation thickness shall be determined by using the Site Insulation work list
Insulation materials and accessories shall be in accordance with the table given in previous section of this method statement.
Application Procedure:
Pipe shall be insulated with mineral wool pipe section a cover for less than and equal to 3” NPS and mineral wool blanket a cover for greater than 3” NPS Dia.
Pipe Insulation having outside diameter of less than 12” (300 mm) shall be secured with stainless Steel wire, pipe insulation having outside diameter of 12” (300 mm) up to 600 mm insulation O.D. shall be secured with 13 mm stainless steel bands and seals and pipe insulation over 600 mm O.D. shall be secured with 19 mm stainless steel bands and seals. The maximum spacing between bands or wires shall not exceed 300 mm.
The circumferential joints on straight piping shall be staggered by a minimum of approximately 150 mm.
Circumferential and longitudinal joints in the second and succeeding layer of multiple layered piping shall be staggered by approximately 150 mm from the joints of the preceding layer.
On long vertical piping runs, clamped insulation supports shall be furnished and installed in accordance with the requirements.
Expansion joint spacing shall be in accordance with specification. Expansion joints shall be packed tightly with fiberglass loose fill insulation.
Insulation adjoining insulated pipe, flanges and valves shall be beveled down and terminated at a suitable distance from the flange to allow easy removal of nuts and stud bolts. The minimum distance shall be equal to the length of the bolt plus 25mm.
Insulation termination shall be provided with a metal flashing collar (end cap).
All exposed insulation shall be weather proofed metal with mastic.
Flanges and valves shall be insulated only in a piping system insulated to conserve energy.
Where there is a need for access for frequent maintenance, the insulation shall be of the removable types, allowance must be made for the removal of flange bolts without disturbing the fixed insulation and permanent vapour barrier. Packing glands shall be left exposed.
For hydrogen service or where heat conservation insulation is not required for flanges, a sheet metal shroud should be installed over flanges for personnel protection. Spectacle blinds shall be left visible for easy accessibility and not totally enclosed by insulation boxes.
If insulation is to be applied over certain austenitic alloy steel (300-series stainless steel) where the operating temperature is between 40oC to maximum services temperature, it is recommended to apply a stress corrosion barrier or specially formulated paint before the application of insulation to prevent stress corrosion cracking and pitting.
All Materials are qualified for use on austenitic stainless steel in accordance with ASTM C795. Test reports to be provided for following tests.
a) ASTM C692 Standard test method evaluate the influence of thermal insulations on external stress corrosion cracking tendency of austenitic. This chemical analysis shall not vary by more than 50% from the chemical analysis of the production lot tested.
b) ASTM C871, Standard test methods for chemical analysis of thermal insulation material for leachable chloride, fluoride, silicate and sodium ions. This chemical analysis shall not vary by more than 50% from the chemical analysis of the production lot tested in accordance with ASTM C692.
If aluminium jacketing is provided on lines with an operating temperature exceeding 400oC (750oF) stainless steel jacketing shall be used at points of contact with insulated surface.
Hot Insulation of Pipe Elbows
Pipe elbows shall be insulated with mineral wool pipe sections cut at job site into shape to fit the elbow.
Insulation of elbows whose outside diameter is less than 300 mm shall be secured with 1.3mm (#16) stainless steel wires.
Elbows whose outside diameter is equal to or greater than 300mm to 600mm shall be secured in place with at least 13mm wide stainless steel bands and seals and insulation outside diameter greater than 610mm shall be secured in place with at least 19mm wide stainless steel bands and seals.
PIPE SUPPORTS: Where the pipe is supported by spring hangers and hanger rods the pipe shall be fully insulated, weatherproofed and placed in preformed cradle before being supported.
MACHINERY: Rotating machinery such as pumps shall be insulated with removable metal box that will allow removal without damaging the insulation in case of maintenance or shutdown. Insulation shall be attached in the fabricated metal box and not on equipment.
Nozzles, Man-ways: Nozzles, man-ways, clean out holes, hand holes, inspection holes, Top nozzles on vertical vessels, Man-ways and side nozzles on vertical vessels etc. shall be insulated in accordance with approved drawings and details.
Vertical Piping:
Secure single layer of insulation with 13mm wide x 0.5mm thick stainless steel bands on 300 mm maximum centres.
Insulation support rings shall be installed for vertical run at every 6.4 meters of Un-interrupted vertical piping.
Pipefittings, including valve bodies shall be insulated with prefabricated fitting covers or mitred sectional pipe insulation securely taped or banded in place.
WEATHERPROOFING (METAL JACKETING)
Hot Vessels and Equipment
Metal jacketing for vessels equipment shall be in accordance with specifications.
All external surfaces of insulation, both indoors and outdoors, shall be provided with weather protection.
Metal jacketing overlaps shall be arranged to shed water.
Caulking compound shall be applied at all possible sources of moisture penetration.
Circumferential overlap at the top tangent lines, transitions and stiffeners shall be a minimum of 150 mm, all other circumferential overlap shall be at 75mm.
For vertical vessels and equipment, s-clips should be used to keep the jacket sheets from sliding down, the length of the s-clip shall equal the overlap, they shall be spaced at 600 mm centres maximum.
The strapping system for the insulation jacketing to be fastened to insulated shell shall consist of 19 mm wide 0.5mm thick band held together with breather springs, when required, and closed seals.
Breather springs shall be provided for all vessels in cyclic service and on all vessels over 2.4 meters in diameter. At least 1 breather spring shall be installed for every 9.1 meters length of banding strap.
Jacketing shall be secured with 19mm wide stainless steel banding spaced at 300 mm maximum centres. A band shall be installed over circumferential overlap on horizontal vessels.
For vertical vessels, one strapping assembly shall be located on each circumferential overlap, which shall pass through the s-clip. All other strapping assembly shall be held in place by j-clips, fastened to the jacket with screws or rivets, to prevent them from sliding down. The j-clips shall be spaced on 1.5 meters maximum centres but not less than 4 per each strapping assembly.
When tensioning the strapping assembly, each breather spring unit, when required, shall be expanded a total of 25% of its normal length.
Rain shields shall be installed at all protrusions and nozzles projecting upwards.
Metal flashing shall be installed at the bottom of insulation support of insulated shells of vessels and equipment.
Longitudinal joints shall have the outer portion facing downwards to allow for draining rainwater.
Sheet metal screws with washers if required shall be installed on longitudinal joints at 150mm centres to hold down jacketing.
Metal screws shall not be installed on circumferential laps.
Exposed edges of metal jacketing shall be machine bent or rolled to eliminate sharp edges.
Hot Piping Cladding / Weather Protection
All external surfaces of insulation, both indoors and outdoors, shall be provided with weather protection.
The metal jacketing to be used shall be as follows:
- All pipe insulation is to be protected with Aluminium smooth sheet as per ASTM B209, alloy 3003-H14, of 0.5mm thickness up to 6” NPS, 0.6mm thickness from 6” to 20” NPS and 0.8mm thickness for greater than 20” NPS, in accordance with applicable standard.
- Metal jacket circumferential and longitudinal sections shall be overlapped a minimum of 50 mm arranged to shed water.
All longitudinal overlap shall be located at 4 o’clock or 8 o’clock position to shed rainwater. Longitudinal overlap shall not be staggered.
Watertight metallic termination cover shall be installed where pipe insulation terminates. Overlap of the cover over adjacent metal jacket shall be secured with screws with washer installed on 150 mm centres.
At each overlap of metal sheets on horizontal pipe, the overlap must have sealant to prevent water ingress into the insulation system. Also, flashing or caulking compound shall be applied at all other possible sources of moisture penetration.
On vertical pipes, “S” – clips on maximum 300mm centres, shall support upper courses.
Removable Type cladding flange cover and Valve boxes shall be installed.
QUALITY CONTROL PROCEDURE
Quality Control of Materials
Only materials approved by the project owner shall be used on site.
If certain materials are not obtainable then the insulation contractor has the right to recommend suitable alternatives and to propose suitable thickness and methods of installation for the proposed alternative materials.
Verify materials received at site are the same as the specified or approved materials. Such check shall include verification of labels, material safety data sheets, delivery receipts and thickness.
Unspecified, unapproved and damaged insulation materials and accessories shall be removed from site.
Ensure that storage of materials will protect them from being damaged by moisture, wind or any other atmospheric factors.
Ensure that insulation is dry, clean and fit for its purpose before weatherproofing is applied.
Quality Control Before Applying Insulation
Prior to release for insulation, Ensure that the following had been checked as required:
- Verify that pressure test have been completed
- Verify that painting of equipment; piping and protrusions have been completed, if required.
- Verify surface to be insulated is dry, clean and free from dust, dirt,
Quality Control During Insulation Application
- Make sufficient check to verify that the materials being applied are the same as the specified or approved materials.
- Verify the insulated items, insulation code (applied versus the insulation code on the isometric drawings), thickness and weatherproofing.
- Verify that the insulation surface is uniform without gaps and voids.
- Inspect tightness of joints and fasteners.
- Inspect the location of bands.
- Verify that the insulation on the expansion joints are properly installed.
- Verify that insulation segments are properly staggered.
Quality Control Before and During Weatherproofing
Verify that the insulation is completely dry and free from gaps.
Inspect for proper overlap of metal flashing.
Verify the application of sealant at the circumferential overlaps of metal jacketing on horizontal pipe and equipment.
Verify the location of bands, screws, s-clips, j-clips and breather springs are as specified.
Final inspection shall be performed to check that no defects are existing. Defects listed below shall be the cause of rejection.
- Concave and / or convex jacketing.
- Torn jacketing
- Interstices and / or separation of jacketing
- Imperfection of water proof on cut (no caulking on cut out of jacketing)
Quality control Records
Client Typical Inspection Plan and applicable inspection checklists shall be followed for inspection Records.
Hot Insulation Repair Procedure
Any damage area insulation and cladding will be removed by cutting and clean the Surface area dusting with cotton rags and reinstall with new insulation material, tie with steel wire by lacing between joints, secure with banding belt with seals if required for additional securement.
Fabricate new cladding materials for the cut out area with proper edge grooved and fix with SS screw as per the distance mentioned in specification waterproof method to be applied for cladding installation with enough overlap joints and apply sealant in all cut out cladding joints to prevent water and moisture entry in to cladded area.
Quality Control Manager (QCM)
Responsibilities and authorities:
Has the responsibility for the proper execution of the following;
- Prepare the Quality Management System
- Conduct internal audits.
- Administer non-conformities and corrective actions.
- Check all procedures established by site staff
- Review, approve, issue and control specific Project Quality Control Plans.
- Manage submission of QA documents to Samsung and represent the company on quality matters towards the customer.
- Collect and evaluate Q.C. procedures provided by subcontractors
- Prepares a Testing Plan and ensure that all tests according to contract are carried out.
- Check materials submission against specifications
- Assist in the preparation of technical submissions.
- Assist in the evaluation of suppliers and subcontractors
Duties and Responsibilities of QC Supervisor/QC Inspector:
Report directly to QC Manager.
Over seeing through spot and routine inspection that the work under execution complies with contract specification requirement, method statements, approved drawings and that the site is utilizing only approved materials.
Deviations and non-conformities are reported to Quality Control Manager for further action.
Ensure that the set quality control procedures are adhered to, implemented and perform training to employee in field where deficiencies are observed.
Ensure that all equipments are properly working and calibrated.
Receive material for permanent work and obtain Saudi Aramco approval for received material.
Assist site personnel in understanding and implementation of quality procedure set for the project.
Any other duty assigned by the Quality Control Manager.
HEALTH AND SAFETY REQUIREMENTS
Material Safety Data Sheets:
Preventive measure and precautions shall be implemented to reduce personal exposure to hazardous dust and fibers.
All materials used on site shall be provided with the material safety data sheets, which will indicate the manufacturer’s recommendation for the safe use of materials.
Personal Protective Equipment:
All personnel working with insulation shall wear the following personal protective equipment as a minimum requirement:
- Safety coverall or long sleeved clothing
- Safety boots
- Hardhats or Helmets with chin straps (for working at heights)
- Dust Masks
- Safety glass with side shields
- Safety Goggles for overhead works
- Hand Gloves (leather palmed gloves or cotton gloves with rubber palm)
- Ear plugs (for noisy areas)
When work over 1.8 meters is required and no other means of fall protection is provided the worker must wear a full body harness with double lanyard and ensure 100% tie – up.
Attachments
- Job safety analysis for Insulation activities
- MSDS for Rockwool
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