Demand for differential pressure gauges in Thang Long Industrial Park II

Thang Long Industrial Park II is located in Hung Yen Province and accommodates manufacturers operating in electronic components, precision engineering, automotive and motorcycle parts, metal processing, industrial machinery, industrial gases and high-technology production. Its tenant list includes companies manufacturing electrical components, electronic materials, automotive products and industrial equipment.

These manufacturing sectors commonly require controlled production environments and stable temperature, humidity, pressure and airborne-dust conditions. Some facilities use cleanrooms for electronic components, optical materials, medical products and precision-assembly operations.

In controlled areas, a differential pressure gauge measures the pressure difference between two locations. It can be installed between rooms, between a cleanroom and a corridor, across a filter or on clean-air equipment.

The reading helps operators identify changes related to doors, supply and return airflow, fan operation, dampers and filter loading.

For cleanroom and MEP contractors, selecting the correct instrument during design reduces the risk of replacement during commissioning. A reputable gauge may still be unsuitable if its measuring range, engineering unit or calibration documentation does not meet the project requirements.

What is a differential pressure gauge?

A differential pressure gauge measures the pressure difference between two points. It normally has a high-pressure port and a low-pressure port connected to the measuring locations through pressure tubing.

The displayed value is the difference between the two pressures rather than the absolute pressure at one point. The instrument does not directly measure cleanliness, airborne particle concentration or airflow volume.

In cleanrooms, it is used to monitor pressure relationships between controlled areas. In AHUs and filter housings, it measures pressure loss across filters.

Differential pressure instruments are available as mechanical dial gauges and digital gauges or transmitters. Mechanical gauges provide local indication. Digital instruments can provide numerical displays, alarms and signals to PLCs or building-management systems.

Why differential pressure matters

Air tends to move from a higher-pressure area to a lower-pressure area. This principle is used to control airflow direction between rooms.

In product-protection areas, the cleaner room is often maintained at a higher pressure than the adjacent space. When a door opens or leakage paths are present, air tends to flow outward, reducing the entry of uncontrolled air.

In containment areas involving dust, chemicals or potentially hazardous materials, the room may be operated below the surrounding pressure to prevent contaminants from spreading outside.

The appropriate pressure differential depends on the production process, cleanliness level, room tightness, number of doors, door-opening frequency, supply airflow, return airflow and contamination-control strategy.

The gauge allows operators to verify the actual pressure condition. It does not regulate pressure unless connected to an automatic control system.

Cleanroom pressure-monitoring applications

Factories in Thang Long Industrial Park II may install differential pressure gauges between production rooms and corridors, between cleanrooms and airlocks or between areas with different control requirements.

The gauge is commonly positioned near the entrance so that operators can check it before entering. The pressure tap should represent room static pressure and should not be located too close to supply grilles, fans or high-velocity airflow.

When a tap is directly exposed to a supply-air jet, dynamic pressure may affect the reading and prevent it from representing average room pressure.

A falling pressure differential may be associated with an open door, poor door sealing, reduced supply airflow, unstable fan performance, damper changes or increased return airflow.

An abnormally high reading may be caused by restricted return airflow, closed dampers, increased supply volume or changes in door condition.

Pressure readings should therefore be interpreted together with HVAC status, airflow and door conditions.

HEPA filter monitoring

Differential pressure gauges are commonly installed upstream and downstream of HEPA filters to monitor pressure loss.

As air passes through the filter media, resistance creates a pressure differential. Dust accumulation normally increases this resistance over time.

Factories should record the initial pressure drop when a new filter is correctly installed, the system is stable and normal operating airflow has been achieved. This value becomes a reference for trend monitoring.

A high differential pressure does not necessarily mean that the filter is damaged. It may result from dust loading, increased airflow, blocked pressure tubing or unsuitable tapping locations.

A low pressure drop does not prove that the filter remains effective. A torn filter, poor gasket sealing or bypass airflow may reduce resistance while compromising particle retention.

HEPA filter assessment should combine differential-pressure monitoring with leakage testing, integrity testing, airflow velocity and airflow-volume measurements.

AHU and HVAC applications

Air-handling units normally include prefilters, medium-efficiency filters and fine filters. Some systems also include HEPA filters in the AHU or at terminal supply points.

Each filter stage has a different initial pressure drop and replacement limit. The same measuring range should not be used for every position.

If the selected range is too high, the pointer moves very little and changes are difficult to observe. If the range is too low, the instrument may exceed full scale or operate outside its suitable range.

Pressure taps must be installed upstream and downstream of the filter section being monitored. Tubing should be secure, leak-free, free from kinks and arranged to prevent condensation.

After a new filter is installed, the initial pressure drop should be recorded at normal airflow. Trend monitoring supports condition-based maintenance rather than relying only on fixed replacement intervals.

Applications on cleanroom equipment

Differential pressure gauges are also used on dynamic pass boxes, air showers, laminar airflow units, dispensing booths, sampling booths, biosafety cabinets and HEPA filter housings.

On a dynamic pass box, the gauge may monitor filter pressure loss or chamber pressure.

On dispensing booths and laminar airflow units, the gauge normally indicates HEPA filter resistance. Some equipment uses electronic sensors together with variable-speed drives to maintain stable airflow velocity.

On terminal HEPA housings and supply-air modules, the gauge helps maintenance personnel identify increasing filter resistance.

Each equipment type has a different airflow rate, filter area, chamber configuration and pressure-drop characteristic. The supplier should review the equipment design before recommending a model.

Common measuring ranges

Low measuring ranges are normally preferred for cleanroom-pressure monitoring because they allow small changes to be observed clearly. Common reference ranges include 0–30 Pa, 0–60 Pa, 0–100 Pa and 0–125 Pa.

For rooms operating under both negative and positive pressure, bidirectional ranges such as -30 to +30 Pa or -60 to +60 Pa may be suitable.

For HEPA filters, dispensing booths, laminar airflow units and filter housings, ranges such as 0–250 Pa, 0–500 Pa, 0–750 Pa or 0–1,000 Pa may be considered.

For AHUs, the range should be selected according to the initial pressure drop, recommended final pressure drop and operating airflow of each filtration stage.

The correct range is not necessarily the largest range. It should cover the maximum expected pressure while allowing meaningful changes to be seen clearly.

Mechanical or digital gauge

A mechanical differential pressure gauge is suitable where local indication is sufficient. It is relatively simple, easy to read and requires no electrical supply for basic operation.

A digital gauge or transmitter is appropriate where alarms, data recording or signal transmission are required. Depending on the model, outputs may include 4–20 mA, 0–10 V, relay contacts or communication protocols.

For periodic local checks, a mechanical gauge is often a practical and economical option.

For critical points requiring continuous monitoring or deviation investigation, an electronic transmitter provides greater functionality. The total cost should also include power supply, signal wiring, control integration, programming, calibration and maintenance.

How to select a supplier in Thang Long Industrial Park II

Application-based selection

The supplier should determine whether the gauge will be used for room pressure, HEPA filter monitoring, AHU filtration or cleanroom equipment.

Each application has different pressure ranges, limits and installation requirements. Selecting only by dial size or price can lead to an unsuitable product.

Understanding of cleanrooms and HVAC systems

Differential-pressure readings are influenced by supply airflow, return airflow, room tightness, doors, fans, dampers and filter condition.

The supplier should understand these relationships to recommend the correct measuring range, pressure-tapping location and installation method.

Vietnam Cleanroom Equipment, also known as VCR Cleanroom, supplies differential pressure gauges and cleanroom equipment to cleanroom contractors, MEP companies, system integrators and industrial factories. Products are selected according to the application, operating conditions and project documentation requirements.

Complete technical documentation

Documentation may include catalogues, technical data sheets, installation instructions, certificates of origin, quality certificates and calibration certificates.

Contractors should confirm documentation requirements during material approval. This prevents a technically suitable instrument from being rejected because its supporting documents are incomplete.

Installation and troubleshooting support

Many incorrect readings are caused by reversed pressure ports, leaking or blocked tubing, condensation or unsuitable pressure-tapping locations.

An experienced supplier should support identification of high- and low-pressure ports, zero adjustment and troubleshooting when readings are unstable.

Coordinated cleanroom-equipment supply

For cleanroom projects, sourcing gauges together with HEPA filter boxes, pass boxes, laminar airflow equipment, interlocks and related products can reduce technical coordination risks.

It also helps contractors coordinate drawings, technical submissions, delivery schedules and after-sales support.

Calibration and acceptance documentation

A calibration certificate should clearly identify the instrument model, serial number, measuring range, calibration points, errors and test conditions.

A quality certificate or factory inspection report does not fully replace an individual calibration certificate.

The calibration interval should be determined according to the criticality of the measuring point, quality-management requirements, manufacturer recommendations and historical stability.

Not every gauge necessarily requires the same interval. A critical production-room measuring point may require stricter control than an instrument used only as a reference on a support system.

Common installation mistakes

The most common error is reversing the high-pressure and low-pressure ports. The pointer may fail to rise or may move in the wrong direction.

Kinked, leaking or blocked tubing can also create incorrect readings. In humid environments, condensation may accumulate and cause unstable indication.

Some mechanical gauges must be installed in the correct orientation. Incorrect mounting or an unstable surface may shift the zero point.

Pressure taps should not be positioned too close to supply grilles, fans or high-velocity airflow. Dynamic pressure in these locations may prevent the reading from representing static pressure.

Pre-commissioning checks

Before commissioning, the project team should verify the model, measuring range, engineering unit, mounting location and pressure-port connections.

When both ports are exposed to equal pressure, the gauge should return to zero within its allowable tolerance.

The system should then be operated to confirm pointer direction and actual differential pressure.

For digital instruments, the power supply, output signal, alarm thresholds, display and PLC or building-management-system connection should also be tested.

A calibrated instrument can still provide an incorrect field reading if the tubing leaks, is blocked or is connected incorrectly. Acceptance testing should therefore evaluate the complete measuring loop.

Frequently asked questions

Where can factories in Thang Long Industrial Park II buy differential pressure gauges?

Factories should select a supplier with practical experience in cleanrooms and HVAC systems that can recommend the measuring range, connection accessories, installation method and calibration documentation.

Can a room-pressure gauge be used for a HEPA filter?

Only when the range and pressure limit are suitable. In practice, room-pressure gauges normally have a lower range than gauges used across HEPA filters.

Is a gauge defective if it does not return to zero?

Not necessarily. Both ports should be exposed to equal pressure, and the tubing, condensation, mounting orientation and zero adjustment should be checked first.

How often should a differential pressure gauge be calibrated?

The interval depends on the criticality of the measuring point, quality-management requirements and historical stability. The factory should establish the interval through risk assessment.

Can a differential pressure gauge confirm cleanroom classification?

No. It only measures pressure difference. Cleanroom classification must be determined through airborne particle counting and other applicable environmental tests.

Differential pressure gauge consultation for Thang Long Industrial Park II

When requesting technical advice or a quotation, factories and contractors should provide the installation location, expected pressure range, display type, output-signal requirements, quantity and documentation requirements.

Vietnam Cleanroom Equipment supplies differential pressure gauges for cleanrooms, AHUs, HVAC systems, HEPA filters, pass boxes, dispensing booths and controlled-air equipment in Thang Long Industrial Park II.

Defining the application accurately from the beginning helps select the correct model, reduces changes during installation and improves project acceptance.