Product Review: 1209 XRA vs T6500 XRA Pressure Gauges for Overpressure Applications

This article was originally published on January 16th, 2023, and updated on November 19, 2025

In many industrial processes, sudden pressure spikes—from water hammer, startup surges, pump cycling or valve events—can place measurement instruments under extreme stress. When a gauge cannot withstand these surges, the result is often permanent damage, unexpected downtime and avoidable maintenance costs. Overpressure gauges are designed to prevent those failures by protecting the Bourdon tube from deformation during high-pressure events.

With more than 170 years of experience solving pressure measurement challenges, Ashcroft understands how demanding these conditions can be. We design gauges that maintain accuracy, survive extreme upsets and help operators protect critical equipment.

Read this article to learn how two pressure gauges equipped with Ashcroft’s XRA built-in overpressure protection—the 1209 and T6500—compare in performance, construction, features and suitability for different industrial environments.

What Problems Do Overpressure Gauges Solve in Industrial Systems?

Overpressure conditions occur when a system experiences sudden or unintended changes in pressure. These events can be triggered by several common process conditions, including:

• Water hammer (a pressure surge caused when moving fluid is forced to stop or change direction abruptly)
• Rapid pump starts or shutdowns
• Valve closures or quick-actuating valves
• Sudden changes in flow or load conditions
• Equipment or control system malfunctions

Pressure instrumentation can only operate within its specified range. When processes exceed that range, the Bourdon tube can permanently deform, causing:

• Premature gauge failure
• Loss of calibration
• Internal component damage
• Potential safety risks and potential leak points

These risks highlight the importance of selecting an overpressure gauge capable of absorbing pressure spikes without losing accuracy or mechanical integrity.

How Does Built-In Overpressure Protection Work?

Ashcroft engineered an internal overpressure protection mechanism (XRA) to protect the Bourdon tube when system pressure exceeds the gauge’s normal operating range. This option is available on Ashcroft's 1209 Pressure Gauge and T6500 XRA Pressure Gauge. 

When the gauge approaches full-scale pressure, the XRA mechanism restricts additional Bourdon tube movement. This changes the tube’s spring rate and prevents permanent deformation during extreme pressure events.

This built-in capability allows the instrument to absorb temporary pressure spikes without damage, reducing the need for external pressure limiting valves and helping extend instrument life. 

How operators know when the gauge is in the overpressure zone

A visual cue on the XRA dial helps operators recognize unsafe conditions and assess whether a different range or protection strategy is required. XRA gauges include a red dial band:

• The white measurement zone shows normal operating pressure.
• The red zone indicates the system has exceeded the gauge’s intended range.

Figure 1. 1209 XRA Overpressure Red Dial Band

How Does the 1209 XRA Gauge Perform Under Overpressure?

The Ashcroft®1209 Pressure Gauge is a solid front, stainless-steel pressure gauge designed for safety, durability and corrosion resistance. With the XRA option, it becomes a strong choice for processes with significant or unpredictable pressure excursions.

1209 XRA Key Features and Benefits

• Up to 417% overpressure protection
  Survives severe pressure spikes without permanent damage, reducing downtime.
  
  
• Solid-front case with full pressure-relief back
  Directs energy away from the operator if a rupture occurs.
  
  
• ±0.5% of span accuracy (ASME Grade 2A)
  Supports precise readings in critical or high-value systems.
  
  
• 4½-inch dial
  Improves readability from longer distances.
  
  
• Red overpressure dial band
  Visually alerts operators to excursions beyond the rated range.
  
  
• Optional PLUS!™ Performance or liquid fill
  Reduces pointer flutter in vibration-intense environments, improving readability and extending gauge life.
  
  
• 316L stainless-steel construction
  Provides strong corrosion resistance for harsh process conditions.
  
  
• Welded socket-to-case design
  Improves leak integrity where containment is essential.

Common 1209 XRA Overpressure Applications 

• Oil & Gas: wellhead monitoring, injection skids, separator units
• Chemical Processing: corrosive media transfer lines, reactor feed systems
• Power Generation: boiler feedwater systems, auxiliary steam lines
• Pulp & Paper: digesters, bleaching systems, recovery operations
• Food & Beverage: high-pressure CIP systems, sterilization lines
• OEM Equipment: hydraulic power units, high-pressure pump skids

How Does the T6500 XRA Gauge Perform Under Overpressure?

The Ashcroft® T6500 XRA Pressure Gauge is a rugged, solid-front gauge designed for demanding process industries. When equipped with the XRA option, it provides durable and reliable performance in environments with vibration, weather exposure or mechanical shock.

T6500 XRA Key Features and Benefits

• Up to 400% overpressure protection
  Allows the gauge to withstand severe and sudden surges in pressure.

• Solid front case with full rear blowout back
  Enhances operator safety by venting rupture energy away from the front.
  
  
• ±1% accuracy standard; ±0.5% optional
  Supports both general-purpose and higher-accuracy applications.
  
  
• 100 mm or 160 mm dial options
  Accommodates panel layouts, equipment size limitations and visibility needs.
  
  
• IP66 / NEMA 4X protection
  Enables use in washdown areas, outdoor installations and environments with dust or water exposure.
  
  
• Optional PLUS!™ Performance
  Dampens vibration and pulsation for stable, readable measurements.
  
  
• Stainless-steel case and wetted parts
  Provides strong corrosion resistance suitable for most process environments.
  
  
• Red overpressure dial band
  Offers clear visual indication of pressure excursions.
  
  
• Welded system design
  Improves durability under high-cycle and high-vibration loading.

Common T6500 XRA Overpressure Applications 

• Offshore Oil & Gas: mud pumps, choke/kill manifolds, stimulation equipment
• Chemical & Petrochemical: compressor discharge lines, reaction systems
• Power Generation: turbine lube oil systems, cooling water skids
• Pulp & Paper: washdown systems, digester feed lines
• Industrial Machinery: hydraulic presses, pump packages
• Food & Beverage: packaging equipment, washdown environments

Figure 2: 1209 XRA and T6500 XRA Comparison Chart

How to Choose the Right Overpressure Gauge for Your Application?

Both gauges provide strong protection against pressure spikes, extend instrument life and reduce the need for external protection devices.

You may prefer the 1209 XRA if you need:

• Superior corrosion resistance
• Standard high accuracy
• A stainless-steel case and wetted system throughout

You may prefer the T6500 XRA if you need:

• A rugged gauge for heavy vibration or outdoor conditions
• Flexibility in dial size and mounting options

Ready to learn more?

With a full understanding of the Ashcroft XRA option and how the two overpressure gauges compare in features and function, you can decide which one would work best for your specific needs. If you have questions, contact a product expert or read other articles listed below. In the meantime, download our guide to learn how you can prevent pressure equipment failure and keep your system going.