Insul-Tek® 250 Steel Piping System
Preinsulated piping systems for above and below ground use for service temperatures up to 250° F.
Typical Uses:
Hot Water
Chilled Water
Fuel Oil
Process Piping
Condensate Lines
Overview
Insul-Tek® 250 Steel System is intended for use on systems ranging in temperature from -350° F to 250 ° F. It is suitable for use above and below ground. Insul-Tek® 250 Steel utilizes the most energy efficient insulation available today, isocyanate polyurethane foam.
The standard protective casings utilized in the system are PVC, HDPE, and FRP. Optional casings, including steel and aluminum, are available.
Insul-Tek® 250 Steel is available in 20' or 40' lengths. Fittings can be prefabricated or field fabricated as site conditions dictate.
Specification Section – Insul-Tek® 250 Steel System
General
Scope of Work
Work includes factory-fabricated, preinsulated steel piping systems for aboveground and belowground service, including straight pipe, fittings, anchors, field joints, end seals, and accessories. The system shall be a factory-engineered composite of steel carrier pipe, polyurethane or polyisocyanurate foam insulation, and protective outer jacket, designed as an integral unit for the specified temperatures and pressures.
Applicable Services
- Closed-loop hot water heating
- Chilled water
- Low-pressure condensate return
- Process fluids compatible with specified materials
System Description
Operating Conditions
Preinsulated pipe shall be suitable for continuous operating temperatures up to 250° F and for the design operating pressure as indicated on project drawings.
System Types
- Belowground: Steel carrier pipe, rigid polyurethane or polyisocyanurate foam insulation, high-density polyethylene (HDPE) or PVC outer casing.
- Aboveground: Steel carrier pipe, rigid polyurethane or polyisocyanurate foam insulation, spiral lock-seam aluminum, galvanized steel, or stainless steel outer jacket.
The system is designed for direct-burial installation (where indicated) without concrete encasement and shall be fully watertight at all factory and field joints.
Products
Carrier Pipe
Carbon steel pipe, ASTM A53 Grade B, Type E (ERW) or seamless, Schedule 40 or Schedule 80 as indicated. For 10-inch and larger, standard weight (approx. 0.375 in. wall) or extra-heavy (approx. 0.500 in. wall). Pipe ends are plain ends for field welding. Corrosion protection — external coatings, internal linings, or cathodic protection — provided as indicated on drawings.
Insulation
Polyurethane Foam:
- Factory injected, rigid, minimum 90% closed-cell content
- Minimum density: 2.0 lb/ft³
- Minimum compressive strength: 30 psi at 75° F
- Maximum K-factor: 0.18 Btu·in/hr·ft²·°F at 75° F per ASTM C518
- Maximum continuous operating temperature: 250° F
Polyisocyanurate Foam (for higher temperature margins):
Factory injected, rigid foam meeting manufacturer's published density, compressive strength, and thermal conductivity criteria for the specified service temperature.
Insulation thickness is per project drawings or manufacturer's standard for required heat loss, but not less than values recommended for the specified service conditions.
Outer Jacket
Belowground: High-density polyethylene (HDPE) or PVC, conforming to ASTM D3350, minimum thickness per manufacturer's standard tables for pipe size (minimum 175 mils for larger diameters). Jacket shall be continuous, watertight, and bonded to the foam.
Aboveground: Spiral lock-seam aluminum, galvanized steel, or stainless steel sheet, thickness per manufacturer's standard tables and project requirements.
Jackets shall be UV resistant where exposed and able to withstand handling and soil loads for buried systems.
Fittings, Anchors, and Accessories
- Fittings: Factory or field-fabricated steel elbows, tees, reducers, and valves with the same wall thickness and grade as carrier pipe. Fittings shall be factory pre-fabricated, insulated, and jacketed using manufacturer-supplied kits, resulting in continuous insulation and a watertight jacket.
- Anchors: Steel anchor plates and collars sized for thermal movements and pressure thrusts, with 3/8-in. steel anchor plates welded to carrier pipe where indicated.
- Field Joint Kits: Include foam insulation, jackets, shrink sleeves, sealants, and accessories to provide a watertight joint equivalent in performance to factory joints.
- End Seals: Each factory pipe length shall include a watertight mastic or elastomeric end seal between carrier pipe and jacket. Field cuts shall receive manufacturer's standard end seals to prevent moisture ingress.
- Optional Leak Detection: Monitoring wire or conduit embedded in foam, compatible with manufacturer's leak detection system.
Installation Summary
General
Install piping per manufacturer's printed instructions and approved shop drawings. Maintain factory-installed end seals intact until joints are made. Carrier pipe joints shall be made by welding, with welders and procedures qualified per applicable codes.
Belowground
Excavate to lines and grades shown; provide uniform bedding and side support per manufacturer's recommendations. After welding and pressure testing of carrier pipe, apply insulation and jacketing per manufacturer's joint kit instructions. Backfill in layers, compacting carefully to avoid jacket damage.
Aboveground
Provide supports at intervals not exceeding manufacturer's recommended span for the specific pipe size and design temperature. Support preinsulated piping on the jacket or on manufacturer-approved saddles — not directly on carrier pipe. Provide guides, anchors, and expansion loops or offsets as shown on drawings.
Field Quality Control
Test carrier pipe prior to insulating field joints where feasible. Test pressures and duration per Division 23/33 or project piping sections. Inspect jackets and field joints for damage, voids, and incomplete seals; repair per manufacturer's recommendations.
Quality Assurance & Submittals
- Manufacturer shall have a minimum of 10 years documented experience manufacturing factory preinsulated steel piping systems for similar applications.
- All system components (pipe, fittings, joints, insulation kits) shall be supplied by a single manufacturer and be fully compatible.
- Foam shall be injected in one shot into the annular space between carrier pipe and jacket to form a bonded composite in a controlled factory environment.
- Deliver pipe and components with end caps or mastic end seals installed at the factory to prevent moisture intrusion.
- Provide manufacturer's standard written warranty for preinsulated piping, not less than one year from Date of Substantial Completion.
Required Submittals include: manufacturer's catalog data and technical bulletins for carrier pipe, insulation (foam type, density, closed-cell content, K-factor, max temp), outer jacket, fittings, anchors, field joint kits, and end seals; shop drawings showing layouts, routing, fittings, anchors, expansion provisions, and field joints; and manufacturer's installation instructions.
