AWWA C111 T-Head Bolt Mechanical Joint Fastener
AWWA C111 T-Head Bolt | Mechanical Joint Fastener for Marine Piping
ANSI/AWWA C111/A21.11 • HSLA COR-TEN Steel (ASTM A242) / SS304 / SS316 • Sizes 5/8"–1-1/4"• Fluoropolymer Coated or Plain • Supplied as Bolt-and-Heavy-Hex-Nut Assembly Set
SINOFASTENER supplies AWWA C111 T-Head Bolts manufactured to ANSI/AWWA C111/A21.11 dimensional and mechanical requirements. Each T-bolt is paired with a matching heavy hex nut to form a complete mechanical joint fastener set for ductile iron pipe flange connections. Available in corrosion-resistant COR-TEN HSLA steel (ASTM A242), SS304, or SS316 stainless steel (ASTM F593/F594), with optional fluoropolymer coating for enhanced chemical resistance. Full material traceability certificates and batch test reports provided for every shipment. Products can be supplied to comply with classification society specification requirements and are available for third-party inspection.
What Is an AWWA C111 T-Head Bolt?
AnAWWA C111 T-Head Bolt (also called a tee-head bolt or hammer-head bolt) is a specialized fastener designed exclusively for mechanical joint (MJ) ductile iron pipe connections. The distinctive T-shaped head slides into the recessed slot cast into the ductile iron bell (socket) of a mechanical joint fitting. When the heavy hex nut is torqued, the T-head rotates into a locked position against the bell recess, clamping the gland onto the rubber gasket to create a pressure-tight seal.
Unlike standard hex bolts, the T-head design eliminates the need to access the back side of the joint — the bolt head is retained entirely within the bell recess. This makes T-bolts ideal for piping installations in confined spaces such as ship engine rooms, pump rooms, and below-deck piping runs where access is limited to one side of the flange. The mechanical joint itself is designed to accommodate pipe deflection angles while maintaining a reliable seal under working pressures up to 350 PSI (for sizes 3"–24").
Marine Applications
Note: Applications listed below are based on typical industry practice for mechanical joint fasteners in marine and water service environments.
| System | Service Type | Typical Pipe Sizes |
|---|---|---|
| Ballast Water System (BWTS) | Intake and discharge piping | 3"–12" |
| Seawater Cooling System | Cooling water intake and return lines | 4"–24" |
| Fire Main System | Emergency firewater piping per SOLAS | 3"–8" |
| Potable Water System | Drinking water distribution aboard vessel | 3"–6" |
| Bilge & Sewage System | Waste water collection and discharge | 3"–10" |
| General Service Water | Non-aggressive water supply service piping | 3"–24" |
Specifications & Materials
General Specifications
| Parameter | Range / Value | Standard Reference |
|---|---|---|
| Standard | ANSI/AWWA C111/A21.11 | AWWA C111/A21.11-17 |
| Bolt Type | T-Head Bolt (Tee-Head / Hammer-Head) | AWWA C111, Section 5 |
| Nut Type | Heavy Hex Nut (matching material grade) | AWWA C111, Section 5 |
| Diameter Range | 5/8", 3/4", 1", 1-1/4" | AWWA C111, Table 5 |
| Length Range | 3"–8-1/2"(custom lengths available) | AWWA C111, Table 5 |
| Pipe Size Coverage | 3"–48"(pipe); 3"–64"(fittings) | AWWA C111, Section 1.1 |
| Thread Standard | UNC Coarse Thread, Class 2A (bolt) / Class 2B (nut) | ASME B1.1 |
| HSLA Material | High Strength Low Alloy Steel (ASTM A242) | AWWA C111, Section 5; ASTM A242 |
| Stainless Steel Options | SS304 / SS316 (bolt per ASTM F593, nut per ASTM F594) | ASTM F593 / ASTM F594 |
| Optional Coating | Fluoropolymer (PTFE) coated; plain; HDG available | Per industry practice |
| Variants | Standard T-Head, X-Long T-Head, Anti-Rotation T-Head | AWWA C111, Section 5; manufacturer catalog |
HSLA Steel Chemical Composition (ASTM A242)
| Element | Requirement |
|---|---|
| Carbon (C) | 0.20% Max |
| Manganese (Mn) | 1.25% Max |
| Sulfur (S) | 0.05% Max |
| Nickel (Ni) | 0.25% Min |
| Copper (Cu) | 0.20% Min |
| Ni + Cu + Cr (Combined) | 1.25% Min |
Source: ASTM A242 / ANSI/AWWA C111/A21.11, Section 5
Mechanical Properties
| Property | HSLA (ASTM A242) | SS304 / SS316 (ASTM F593) |
|---|---|---|
| Min. Yield Strength | 45,000 PSI (310 MPa) | 45,000 PSI (310 MPa) |
| Min. Elongation in 2 in. | 20% | Per ASTM F593 |
| Tensile Strength | Per ASTM A242 | 85,000–140,000 PSI |
Source: ANSI/AWWA C111/A21.11, Section 6; ASTM A242; ASTM F593
Proof Load Requirements (Bolt + Nut Assembly)
| Bolt Size | Proof Load |
|---|---|
| 5/8" | 9,000 lbf |
| 3/4" | 13,500 lbf |
| 1" | 25,000 lbf |
| 1-1/4" | 40,000 lbf |
Source: ANSI/AWWA C111/A21.11, Table 7
Installation Torque by Pipe Size
| Pipe Size (in.) | Bolt Size | Bolt Qty | Torque (ft-lb) |
|---|---|---|---|
| 3" | 5/8" | 4 | 45–60 |
| 4"–24" | 3/4" | 4–16 | 75–90 |
| 30"–36" | 1" | 20–24 | 100–120 |
| 42"–48" | 1-1/4" | 28–32 | 120–150 |
Source: ANSI/AWWA C111/A21.11, Appendix A, Table A.1
T-Head Bolt Dimensions
| Size (in.) | A ±0.05 | B (Shank) | C (Length) | F (Thread Dia.) | H (Head Height) | J (Head Width) | R (Head Thickness) | D* (Thread Length) | Threads/in. |
|---|---|---|---|---|---|---|---|---|---|
| 5/8 × 3 | 1.50 | 0.625 | 3.00 | 0.625 | 1.062 | 0.625 | 0.312 | 2.00 | 11 |
| 3/4 × 3-1/2 | 1.75 | 0.750 | 3.50 | 0.750 | 1.250 | 0.750 | 0.375 | 2.50 | 10 |
| 3/4 × 4 | 1.75 | 0.750 | 4.00 | 0.750 | 1.250 | 0.750 | 0.375 | 3.00 | 10 |
| 3/4 × 4-1/2 | 1.75 | 0.750 | 4.50 | 0.750 | 1.250 | 0.750 | 0.375 | 3.00 | 10 |
| 3/4 × 5 | 1.75 | 0.750 | 5.00 | 0.750 | 1.250 | 0.750 | 0.375 | 3.00 | 10 |
| 1 × 6 | 2.25 | 1.000 | 6.00 | 1.000 | 1.625 | 1.000 | 0.500 | 3.00 | 8 |
| 1-1/4 × 6-1/2 | 2.50 | 1.250 | 6.50 | 1.250 | 2.000 | 1.250 | 0.625 | 3.50 | 7 |
All dimensions in inches. B = unthreaded shank diameter; D* = thread length (tolerance +3/-0). Source: ANSI/AWWA C111/A21.11, Table 5
Product Configurations
1. Standard COR-TEN T-Bolt & Nut
High Strength Low Alloy (HSLA) weathering steel per ASTM A242 and ANSI/AWWA C111. The natural patina formed by COR-TEN steel provides atmospheric corrosion resistance, making it suitable for outdoor and marine environments. Supplied plain (uncoated) with matching heavy hex nut. This is the standard configuration for most water and wastewater piping applications.
2. Fluoropolymer Coated T-Bolt
HSLA steel T-bolts with a thermally cured, resin-bonded fluoropolymer (PTFE) coating. Film thickness: 0.3–0.4 mil per coat, applied in 3–4 coats. Provides enhanced chemical resistance and a dry lubricating effect that facilitates future disassembly. VOC-compliant formulation. Color-coded coating available for material identification.
3. Stainless Steel T-Bolt (SS304 / SS316)
T-bolt dimensions per ANSI/AWWA C111/A21.11; bolt material per ASTM F593 (SS304 or SS316); heavy hex nut per ASTM F594. Stainless steel nuts are factory-coated with fluoropolymer — blue for SS304, red for SS316 — to prevent galling during installation. Recommended for aggressive seawater and chlorinated water environments.
4. Anti-Rotation T-Head Bolt
Features a dimensioned flat (dimension E) on the shank that engages the gland slot to prevent bolt spin during nut tightening. Essential for restricted-access installations where the back side of the joint cannot be held. Available in HSLA steel for pipe sizes 4"through 24". Max. load per bolt: 7,500 lbs. Manufactured per ANSI/AWWA C111/A21.11 with UNC 2A threads per ASME B1.1.
Why Choose SINOFASTENER for AWWA C111 T-Head Bolts?
36 Years of Fastener Manufacturing: Established in 1990, SINOFASTENER brings over three decades of experience in producing industrial and marine fasteners to exacting dimensional standards.
Full AWWA C111 Compliance: All T-head bolts manufactured to ANSI/AWWA C111/A21.11 dimensional, chemical, and mechanical requirements. Threads per ASME B1.1 UNC Class 2A/2B. Complete proof load testing per Table 7.
Multiple Material Options: COR-TEN HSLA steel (ASTM A242), SS304, and SS316 stainless steel (ASTM F593/F594). Fluoropolymer coating available for enhanced corrosion protection in aggressive marine environments.
Complete Documentation: Material test certificates, chemical composition reports, and batch traceability provided with every shipment. Products can be supplied to comply with classification society specification requirements. Available for third-party inspection. Annual production capacity: 50,000 tons.
Standards Reference
- ANSI/AWWA C111/A21.11 — Rubber-Gasket Joints for Ductile-Iron Pressure Pipe and Fittings (current edition: 2017)
- ASTM A242 — Standard Specification for High-Strength Low-Alloy Structural Steel (HSLA material for T-bolts)
- ASTM F593 — Standard Specification for Stainless Steel Bolts, Hex Cap Screws, and Studs (SS304/SS316 bolt material)
- ASTM F594 — Standard Specification for Stainless Steel Nuts, Hex Cap, Hex Flange, and Hex Coupling (SS304/SS316 nut material)
- ASME B1.1 — Unified Inch Screw Threads (UNC thread standard, Class 2A/2B)
- ASME B18.2.1 — Square, Hex, Heavy Hex, and Askew Head Bolts and Hex Cap Screws (heavy hex nut dimensions)
FAQ
Q1: What is a T-Head Bolt and how does it work in a mechanical joint?
A T-Head Bolt (tee-head bolt) has a hammer-shaped head that slides into the recessed slot in a ductile iron mechanical joint bell. When the heavy hex nut is torqued, the T-head rotates 90 degrees and locks against the bell recess, clamping the gland onto the rubber gasket. This creates a pressure-tight seal without needing access to the back side of the joint — ideal for confined pipe installations in ship engine rooms and below-deck spaces.
Q2: How does AWWA C111 determine bolt size for different pipe diameters?
AWWA C111 specifies four bolt diameters based on pipe size: 5/8"for 3"pipe (45–60 ft-lb torque), 3/4"for 4"–24"pipe (75–90 ft-lb), 1"for 30"–36"pipe (100–120 ft-lb), and 1-1/4"for 42"–48"pipe (120–150 ft-lb). The bolt quantity increases with pipe diameter, ranging from 4 bolts on 3"pipe to 32 bolts on 48"pipe.
Q3: Why is COR-TEN steel specified for AWWA C111 T-bolts?
COR-TEN steel (HSLA per ASTM A242) is a weathering steel that forms a protective oxide patina when exposed to atmospheric moisture. This gives it superior corrosion resistance compared to plain carbon steel without requiring additional coating. It meets the AWWA C111 chemical requirements (Ni 0.25% min, Cu 0.20% min, combined Ni+Cu+Cr 1.25% min) and provides a minimum yield strength of 45,000 PSI with 20% elongation, ensuring both durability and ductility in mechanical joint applications.
Q4: What is the fluoropolymer coating and when is it needed?
The fluoropolymer (PTFE) coating is a resin-bonded, thermally cured dry lubricant applied at 0.3–0.4 mil per coat (3–4 coats total). It provides enhanced chemical resistance against corrosive soils, seawater splash, and chlorinated environments. The dry lubricating effect also reduces friction during installation and facilitates future disassembly. For marine applications with direct seawater exposure, SS316 stainless steel T-bolts are recommended over coated HSLA bolts.
Q5: What is the difference between Standard and Anti-Rotation T-Head Bolts?
Standard T-Head Bolts have a round shank that can rotate freely in the bell slot during installation. Anti-Rotation T-Head Bolts feature a dimensioned flat on the shank (dimension E) that engages the gland slot to prevent the bolt from spinning when the nut is tightened. This is essential in confined-access locations where the installer cannot hold the bolt head from the opposite side. Anti-rotation variants are available for pipe sizes 4"through 24"with a maximum load of 7,500 lbs per bolt.
Q6: Which stainless steel grade should I use for marine piping?
SS316 is recommended for direct seawater exposure, ballast water systems, and chlorinated environments due to its molybdenum content (2–3%), which provides superior pitting and crevice corrosion resistance. SS304 is suitable for potable water systems, bilge lines, and general service water where chloride levels are moderate. Stainless steel nuts are factory-coated with fluoropolymer (blue for SS304, red for SS316) to prevent galling during tightening.
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