Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Expansion Fittings and Loops for Piping
…172 unchanged lines
## Each expansion device shall be selected for the maximum and minimum metal temperatures and the design pressure of the service in which it is installed.
−## Thermal movement shall be calculated for each pipe run segment as ΔL = α × L × ΔT, where α is the material thermal expansion coefficient, L is the anchored length, and ΔT is the temperature change from installation to operating condition.
−
−## The thermal expansion coefficient varies by pipe material and is the single largest driver of calculated movement. {note}
−
−### Carbon steel grows about 0.78 in per 100 ft per 100°F (α ≈ 6.5 × 10⁻⁶ in/in·°F); stainless steel α ≈ 9.6 × 10⁻⁶ and copper α ≈ 9.5 × 10⁻⁶ in/in·°F move roughly half again as much; CPVC at α ≈ 34 × 10⁻⁶ moves several times more and almost always needs deliberate expansion provisions. {note}
−
−## The temperature difference used in sizing shall be the full range the pipe experiences, from the coldest installation or shutdown condition to the maximum operating temperature.
−
−### Typical HVAC ranges are chilled water 40-60°F (ΔT vs. ambient ≈ 30-50°F), hydronic hot water 120-200°F (ΔT ≈ 100-170°F), high-temperature hot water 250-400°F (ΔT ≈ 150-350°F), and low-pressure steam ≈ 215-250°F. {note}
−
```datasheet
label: System service
…11 unchanged lines
```datasheet
+label: Design pressure
+type: range
+min: 50
+max: 300
+step: 25
+unit: psig
+default: 150
+```
+
+## Thermal movement shall be calculated for each pipe run segment as ΔL = α × L × ΔT, where α is the material thermal expansion coefficient, L is the anchored length, and ΔT is the temperature change from installation to operating condition.
+
+```datasheet
label: Pipe material (sets thermal coefficient)
type: select
…7 unchanged lines
```datasheet
−label: Design pressure
+label: Calculated thermal movement per run (ΔL)
type: range
−min: 50
−max: 300
−step: 25
−unit: psig
−default: 150
+min: 0.25
+max: 12
+step: 0.25
+unit: in
+default: 1
```
+## The thermal expansion coefficient varies by pipe material and is the single largest driver of calculated movement. {note}
+
+### Carbon steel grows about 0.78 in per 100 ft per 100°F (α ≈ 6.5 × 10⁻⁶ in/in·°F); stainless steel α ≈ 9.6 × 10⁻⁶ and copper α ≈ 9.5 × 10⁻⁶ in/in·°F move roughly half again as much; CPVC at α ≈ 34 × 10⁻⁶ moves several times more and almost always needs deliberate expansion provisions. {note}
+
+## The temperature difference used in sizing shall be the full range the pipe experiences, from the coldest installation or shutdown condition to the maximum operating temperature.
+
```datasheet
label: Maximum operating temperature
…6 unchanged lines
```
−```datasheet
−label: Calculated thermal movement per run (ΔL)
−type: range
−min: 0.25
−max: 12
−step: 0.25
−unit: in
−default: 1
−```
+### Typical HVAC ranges are chilled water 40-60°F (ΔT vs. ambient ≈ 30-50°F), hydronic hot water 120-200°F (ΔT ≈ 100-170°F), high-temperature hot water 250-400°F (ΔT ≈ 150-350°F), and low-pressure steam ≈ 215-250°F. {note}
# Device Selection {toc}
…7 unchanged lines
## The rubber sphere joint is the default for typical hydronic HVAC below 200°F. {note}
−### More than two-thirds of commercial HVAC hydronic work uses a single-sphere EPDM rubber joint rated 150 psig and 200°F with Class 150 flanged ends; it is compact, absorbs axial, lateral, and angular movement, and doubles as a mild vibration buffer. It is the 80%-case default and the starting point unless temperature, pressure, or movement rules it out. {note}
+### More than two-thirds of commercial HVAC hydronic work uses a single-sphere EPDM rubber joint rated 150 psig and 200°F with Class 150 flanged ends; it is compact, absorbs axial, lateral, and angular movement, and doubles as a mild vibration buffer. It is the default specified here and the starting point unless temperature, pressure, or movement rules it out. {note}
## Metallic bellows joints dominate steam and high-temperature hot-water service. {note}
…29 unchanged lines
## A mismatched flange class makes the joint the weak link in the system. {note}
−### Expansion joints are frequently ordered Class 150 flanged out of habit while the adjacent system is Class 300; the joint then becomes the lowest-rated component in the run. The end-connection class shall be verified against the system class, not assumed. {note}
+### Expansion joints are frequently ordered Class 150 flanged out of habit while the adjacent system is Class 300; the joint then becomes the lowest-rated component in the run. The end-connection class shall be verified against the system class, not assumed.
### Flanged connections shall conform to ASME B16.5 for the specified pressure class.
…23 unchanged lines
## Metallic bellows joints shall be furnished as the sub-type required by the piping geometry and the structural anchor capacity, and the sub-type shall be scheduled.
+```datasheet
+label: Bellows joint sub-type
+type: radio
+options:
+ - Single unrestrained (axial)
+ - Tied (lateral / angular)
+ - Hinged (single-plane angular)
+ - Gimbal (multi-plane angular)
+ - Pressure-balanced
+ - Externally pressurized
+default: Single unrestrained (axial)
+```
+
## The bellows sub-type determines what movement the joint absorbs and whether it imposes pressure thrust on the anchors. {note}
…12 unchanged lines
## Bellows shall be austenitic stainless steel.
−### Single-ply 304 stainless steel is the default for building steam and HTHW service; 316 stainless or nickel alloy is required where the fluid or process environment demands higher corrosion resistance. {note}
−
−## The factory cycle-life rating shall meet or exceed the specified minimum for the service.
−
−## Building HVAC systems see a modest but real number of thermal cycles over their life, and the cycle rating must cover them with margin. {note}
−
−### A typical building system experiences 1,000-5,000 thermal cycles over a 30-year life; a 3,000-cycle minimum suits daily-cycling systems, while condensate and domestic hot-water systems that cycle frequently warrant 10,000 cycles. Under-rating the bellows for cycle count is a slow-failure mode that does not show up at startup. {note}
−
```datasheet
−label: Bellows joint sub-type
−type: radio
−options:
− - Single unrestrained (axial)
− - Tied (lateral / angular)
− - Hinged (single-plane angular)
− - Gimbal (multi-plane angular)
− - Pressure-balanced
− - Externally pressurized
−default: Single unrestrained (axial)
−```
−
−```datasheet
label: Bellows material
type: select
…5 unchanged lines
```
+### Single-ply 304 stainless steel is the default for building steam and HTHW service; 316 stainless or nickel alloy is required where the fluid or process environment demands higher corrosion resistance. {note}
+
+## The factory cycle-life rating shall meet or exceed the specified minimum for the service.
+
+## Building HVAC systems see a modest but real number of thermal cycles over their life, and the cycle rating must cover them with margin. {note}
+
+### A typical building system experiences 1,000-5,000 thermal cycles over a 30-year life; a 3,000-cycle minimum suits daily-cycling systems, while condensate and domestic hot-water systems that cycle frequently warrant 10,000 cycles. Under-rating the bellows for cycle count is a slow-failure mode that does not show up at startup. {note}
+
+### The number of bellows plies shall be specified for each metallic expansion joint based on the thermal cycling demands of the service.
+
```datasheet
label: Number of plies
…5 unchanged lines
```
+### The rated axial movement of each metallic bellows expansion joint shall be specified based on the piping thermal movement it must accommodate.
+
```datasheet
label: Rated axial movement
…20 unchanged lines
## Rubber expansion joints shall comply with ASTM F2686 and shall be furnished as the single-sphere, multi-sphere, or spool configuration required for the movement.
−## The sphere type is compact and the spool type accommodates larger axial movement. {note}
−
−### A single-sphere joint is the most compact and is the standard choice for hydronic HVAC; a spool (straight-body) joint accommodates greater axial movement where the run requires it. {note}
−
−## The elastomer compound shall be selected for the fluid and temperature of the service.
−
−### EPDM is the default for water, glycol, and steam condensate; Neoprene suits general service; Nitrile is required where the water may be oil-contaminated. {note}
−
−## The default rubber sphere joint for hydronic HVAC shall be EPDM with nylon reinforcement, rated 150 psig and 200°F maximum, with Class 150 flanged ends and galvanized carbon-steel control rods.
−
−## Control rods shall be furnished on rubber joints to limit extension under pressure, in accordance with MSS SP-129.
−
−## Control rods shall be set to allow full rated movement while stopping extension at 150% of working pressure.
−
−## Without control rods the joint can be over-extended at startup and fail. {note}
−
−### Control rods limit the joint's extension to its rated travel and prevent over-extension under full pressure or vacuum at zero-flow startup; an uncontrolled joint can be torn open before flow is even established, voiding the warranty. {note}
−
```datasheet
label: Rubber joint configuration
…6 unchanged lines
```
+## The sphere type is compact and the spool type accommodates larger axial movement. {note}
+
+### A single-sphere joint is the most compact and is the standard choice for hydronic HVAC; a spool (straight-body) joint accommodates greater axial movement where the run requires it. {note}
+
+## The elastomer compound shall be selected for the fluid and temperature of the service.
+
```datasheet
label: Elastomer compound
…6 unchanged lines
```
+### EPDM is the default for water, glycol, and steam condensate; Neoprene suits general service; Nitrile is required where the water may be oil-contaminated. {note}
+
+## The default rubber sphere joint for hydronic HVAC shall be EPDM with nylon reinforcement, rated 150 psig and 200°F maximum, with Class 150 flanged ends and galvanized carbon-steel control rods.
+
+## Control rods shall be furnished on rubber joints to limit extension under pressure, in accordance with MSS SP-129.
+
```datasheet
+label: Control rods
+type: radio
+options:
+ - Furnished with control rods
+ - Not required (verify with Engineer)
+default: Furnished with control rods
+```
+
+## Control rods shall be set to allow full rated movement while stopping extension at 150% of working pressure.
+
+## Without control rods the joint can be over-extended at startup and fail. {note}
+
+### Control rods limit the joint's extension to its rated travel and prevent over-extension under full pressure or vacuum at zero-flow startup; an uncontrolled joint can be torn open before flow is even established, voiding the warranty. {note}
+
+### The rated working pressure of the rubber expansion joint shall be specified consistent with the pressure of the service in which it is installed.
+
+```datasheet
label: Rated working pressure
type: range
…5 unchanged lines
```
+### The maximum service temperature of the rubber expansion joint shall be specified consistent with the fluid, temperature, and elastomer compound selected for the service.
+
```datasheet
label: Maximum service temperature
…6 unchanged lines
```
−```datasheet
−label: Control rods
−type: radio
−options:
− - Furnished with control rods
− - Not required (verify with Engineer)
−default: Furnished with control rods
−```
+### The rated axial movement of each rubber expansion joint shall be specified, and control rods shall be provided to limit extension to that rating.
```datasheet
…73 unchanged lines
## Anchors and guides integral to an expansion device shall be furnished and located in accordance with EJMA and MSS SP-129.
+```datasheet
+label: Guide and anchor locations
+type: text
+drawing_ref: anchor and guide layout
+default: deferred
+```
+
## Anchors direct movement; guides keep the pipe and bellows straight. {note}
…2 unchanged lines
## Main anchors shall be provided on both sides of every unrestrained metallic bellows joint and shall be designed for the full pressure thrust plus pipe weight and friction reactions.
+```datasheet
+label: Anchor type at device
+type: radio
+options:
+ - Full (main) anchor - resists full thrust
+ - Intermediate (directional) anchor
+default: Full (main) anchor - resists full thrust
+```
+
## Omitting or undersizing main anchors transfers pressure thrust into equipment and structure. {note}
…2 unchanged lines
## The first guide shall be located no more than 4 pipe diameters from the anchor face.
+```datasheet
+label: First guide distance from anchor
+type: range
+min: 1
+max: 4
+step: 0.5
+unit: pipe dia.
+default: 4
+```
+
## The second guide shall be located no more than 14 pipe diameters from the first guide.
…8 unchanged lines
## Coordinating anchor loads with the structural engineer is a commonly missed step. {note}
−### Full anchor forces combine pressure thrust, pipe weight, and friction and often require local reinforcing at the structural penetration; this coordination is routinely overlooked and shall be a tracked deliverable. {note}
+### Full anchor forces combine pressure thrust, pipe weight, and friction and often require local reinforcing at the structural penetration; this coordination is routinely overlooked and shall be a tracked deliverable.
## Expansion devices shall not be installed across building seismic joints or building separations.
### Thermal joints are not designed for multi-directional seismic displacement; a separate seismic expansion coupling, coordinated through [[sync/hangers-and-supports]], is required where piping crosses a building separation. {note}
−```datasheet
−label: Anchor type at device
−type: radio
−options:
− - Full (main) anchor - resists full thrust
− - Intermediate (directional) anchor
−default: Full (main) anchor - resists full thrust
−```
−
−```datasheet
−label: First guide distance from anchor
−type: range
−min: 1
−max: 4
−step: 0.5
−unit: pipe dia.
−default: 4
−```
−
−```datasheet
−label: Guide and anchor locations
−type: text
−drawing_ref: anchor and guide layout
−default: deferred
−```
−
# Testing {toc}
…66 unchanged lines
## The manufacturer shall warrant each expansion device against defects in materials and workmanship for the period specified.
−## Warranty coverage is preserved only when the device is installed within its rated movement and control limits. {note}
−
−### Most manufacturers void coverage if a joint is over-extended, over-compressed, or installed without the required control rods or cold-set; the installation requirements of this standard are also the conditions of the warranty. {note}
−
```datasheet
label: Manufacturer warranty period
…6 unchanged lines
```
+## Warranty coverage is preserved only when the device is installed within its rated movement and control limits. {note}
+
+### Most manufacturers void coverage if a joint is over-extended, over-compressed, or installed without the required control rods or cold-set; the installation requirements of this standard are also the conditions of the warranty. {note}
+
# Spare Parts {toc}
## The Contractor shall furnish the spare parts and maintenance materials specified for the installed devices.
−## Spare packing shall be furnished for slip/sleeve expansion joints.
−
−### Slip joints are the only covered device with a routinely replaceable wear part; a spare packing set per joint size keeps the system maintainable without a special order at the first repack. {note}
−
```datasheet
label: Spare parts to furnish
…7 unchanged lines
- Spare gaskets per flanged connection size
```
+
+## Spare packing shall be furnished for slip/sleeve expansion joints.
+
+### Slip joints are the only covered device with a routinely replaceable wear part; a spare packing set per joint size keeps the system maintainable without a special order at the first repack. {note}