Locally Actuated Partial Stroke Testing

What is Partial Stroke Testing (PST)?

Partial stroke testing is a maintenance and testing technique used in industries that involve safety-critical devices.

It involves intentionally moving a valve or actuator only partially from its fully closed or fully open position to verify its functionality without fully interrupting the process or system it controls.

Why is PST performed?

The LAPST system is the first partial stroke testing system made in Saudi Arabia

MADE IN SAUDI ARBAIA

This story is part of an ongoing series on Saudi Aramco technologies that are being commercialized by Aramco’s licensing arm, Saudi Aramco Technologies Company.

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PRODUCT DATASHEET

LAPST

Operating Pressure: 25-145 PSI
Operating Temperature: -10° to 60° C
Air Quality: ISA 7.0.01 (40 pm max)
Port Size: 1/4 inch
Protection Class (IEC 144): IP 66
Weight (g): Approx. 5 kg
Mounting: Front panel mounting
Application note: Operate by hand only
Housing Material: lonized Aluminum
Response time: 0.2 Second from test initiation
Test Time: ~ 10-15 seconds
PST Movement: PST automatically terminated after 15 seconds

Locally Actuated Partial Stroke Testing

Retrofit Installation Steps (Simplified)

Pre-Installation

1.Plant to evaluate and decide if ZV can be completely isolated or its position can be held in place using the ZV hand-wheel

2.Air Supply must be shut down before the removal or installation of any component.

Installation

1.Bolt the LAPST device to the actuator panel while ensuring accessibility and visibility of the position indicator

2.Tubing between the air regulator and the “Supply Port” of the LAPST device and between the solenoid valve and the “Actuator Port” of the LAPST device is to be installed.

3.Once the tubing is installed, restore the air supply and check for any air leaks. If no leaks are present then the valve can be returned to normal operation.

Calibration – to be performed by IVM during retrofit

Locally Acculated Partial Stroke Testing

SIMPLE OPERATIONS

Step 1

Step 2

Step 3

Switch from the isolation line to the partial stroke testing line by turning the levers on the isolation valves.

Hold down the push button to begin the partial stroke test. As the push button is engaged, the valve will slowly turn until the predefined testing point is reached. Once the operator disengages the push button, the valve will return to its normal position.

Once the test is complete, the operator can switch back to the main line to fully bypass the PST device, as an additional safety contingency.

Locally Acculated Partial Stroke Testing

IVM's LAPST Safety & Reliability Features

Zero interference with safety functions

Fully Mechanical

No interruption to process flow

Corrosion Resistant & 1P66 Certified

Bypass Line & Manual Override

Manually Actuated

Overshoot Protection

Benefits from a

valve manufacturer's standpoint

Reduced Time

Setup, calibration and testing time can be drastically reduced

Reduced Complexity

• Reduced training requirements
• Setup and calibration can be simplified
• Testing will be easier to perform

Reduced Costs

• Device itself will cost less than the traditional technologies
• No additional connections, external communicators, and specialized programs
• PST using LAPST System is much simpler to perform

Benefits to valve manufacturer also apply to

EPC Contractors

Reduced Time

Time taken to install and commission ZVs can be drastically reduced with the new LAPST system

Reduced Complexity

• Eliminate all wiring, cabling, LCPs, 1/0 cards, programs for PST
• Documentation, drawings, manuals are

Reduced Costs

Reduced man hours, installation and commissioning requirements, and engineering result in much lower costs

Significant Benefits to

end - users (i.e. SA plants and facilities)

Lower CAPEX

LAPST device costs are cheaper than traditional technologies
No associated equipment (LCP, 1/0 cards, cables, wiring, etc.)

Lower OPEX

No passive air or energy consumption
Reduced maintenance requirements

Simpler Operation

Simpler setup, calibration, and operation

Better Reliability

Zero risk of nuisance trips and zero interference with SIS

Environmentally Friendly

No passive air or energy consumption, zero emissions

Compatibility and Life Cycle

Longer lifetime, better compatibility