Differential Pressure Switch

Product Description

The AI-32 Differential Pressure Switch is built for cleanroom pressure control, isolation room monitoring, and HVAC filter alarm applications where an instant ON/OFF alert is needed rather than a continuous digital readout. It senses even minor pressure differences between two points and switches an electrical contact the moment a preset threshold is crossed, triggering connected alarms, BMS panels, or fan/damper controls.

A field-adjustable setpoint with an integral calibrated scale lets facility teams tune the switching point on-site without a manometer, and a transparent protective cover guards the setting from accidental changes while maintaining IP54 protection serving as a practical fit for pharma, hospital, and industrial cleanroom environments where GMP audit readiness depends on documented, tamper-resistant pressure control.

Features

• Highly Precise Pressure Switching
  
  Detects minute differential pressure shifts, giving reliable early warning for cleanroom filter monitoring and airflow-loss conditions before they affect classified space compliance.
  
  
• Field-Adjustable Setpoint
  
  The switching point is set directly on the integral calibration scale, so commissioning and re-validation during cleanroom requalification don't require external calibration tools.
  
  
• Stable, Audit-Ready Operation
  
  Consistent switching accuracy under continuous duty supports the documented pressure control expected in pharmaceutical cleanroom and hospital isolation room qualification records.
  
  
• Durable Industrial Construction
  
  A rugged housing with a transparent tamper-evident cover protects the setpoint from unauthorized adjustment, an important control point for audit-ready monitoring.
  
  
• IP54 Protected Enclosure
  
  Shields internal components from dust ingress, suited to cleanroom anterooms, gowning areas, and adjacent mechanical spaces.
  
  
• Compact, Simple Installation
  
  Wall or panel mounting fits directly into AHUs, ducts, or cleanroom wall penetrations without major retrofit work.
  
  
• Air & Non-Corrosive Gas Compatible
  
  Rated for air and clean, non-corrosive gaseous media, matching standard cleanroom and pharma HVAC service conditions.

Applications

• Cleanroom Pressure Cascade Control
  
  Maintains the pressure differential between adjoining cleanrooms and gowning areas, alerting staff the moment a room falls out of its required positive or negative pressure cascade, which is central to contamination control in pharma and semiconductor cleanrooms.
  
  
• Isolation Room Pressure Alarming
  
  Confirms hospital isolation rooms hold their required negative (infectious) or positive (protective) pressure state relative to the corridor, supporting HTM 03-01 and ASHRAE 170-aligned pressure monitoring practices.
  
  
• HEPA and Terminal Filter Blockage Detection
  
  Monitors pressure drop across HEPA and bag filters serving cleanroom AHUs, flagging blockage before airflow and particle count are compromised.
  
  
• AHU and Fan Failure Monitoring
  
  Detects loss of differential pressure across a fan or AHU stage, giving early warning of fan failure or belt slippage before it affects downstream room classification.
  
  
• BMS/SCADA Pressure Alarm Integration
  
  The switch's relay output ties into building management and SCADA systems, so pressure excursions in classified areas trigger automated alerts and logged events for 21 CFR Part 11- style audit trails.
  
  
• Gowning Room and Airlock Verification
  
  Confirms correct pressure staging through airlocks and gowning rooms, a common point of scrutiny during GMP facility audits.

Specifications

{{table-component}} 

Frequently Asked Questions (FAQs)

1. Why is differential pressure important in a cleanroom?

Differential pressure prevents airborne contaminants from moving between adjacent rooms. Maintaining the correct pressure difference ensures that clean air flows from cleaner areas to less clean areas, helping maintain cleanroom classification and product quality.

2. Why use a differential pressure switch instead of a differential pressure transmitter?

A differential pressure switch is ideal when you only need an ON/OFF action. It activates an electrical contact whenever the pressure exceeds or falls below a preset value, making it suitable for alarms, fan interlocks, and filter replacement alerts. A transmitter, on the other hand, provides a continuous pressure reading for monitoring and trending.

3. How does the AI-32 protect pharmaceutical cleanrooms?

The AI-32 continuously monitors pressure differences between cleanroom zones. If the pressure falls below the preset limit, it immediately activates an alarm or control signal, allowing operators to take corrective action before contamination risks increase.

4. Can the AI-32 be used for HEPA filter monitoring?

Yes. As HEPA filters become loaded with dust, the pressure drop across the filter increases. The AI-32 detects this increase and can trigger an alarm when the filter reaches the replacement pressure, helping avoid unnecessary maintenance while ensuring proper airflow.

5. Can the AI-32 monitor fan operation?

Yes. The pressure switch can verify that supply or exhaust fans are generating the required airflow. If the fan fails or airflow drops below the preset level, the switch changes state and activates an alarm or control output.

6. What happens if cleanroom pressure falls below the required limit?

When the measured pressure reaches the configured switching point, the AI-32 changes its electrical contact. This signal can activate audible alarms, warning lights, Building Management Systems (BMS), or HVAC interlocks so operators are notified immediately.

7. Can the AI-32 be used in isolation rooms and hospital applications?

Yes. The AI-32 is suitable for positive-pressure operating theatres, isolation rooms, intensive care units, and hospital clean areas where maintaining the correct room pressurization is essential for infection control.

8. Can one pressure switch monitor both positive and negative pressure rooms?

Yes. The AI-32 measures the pressure difference between two points and can therefore be configured for either positive-pressure or negative-pressure monitoring depending on the installation.

9. How is the switching pressure adjusted?

The switching threshold is field adjustable using the built-in adjustment mechanism. This allows installers to set the required switching pressure for filter monitoring, room pressurization, or airflow applications.

10. What pressure ranges are commonly used in cleanrooms?

Most pharmaceutical cleanrooms operate with pressure differences between approximately 10 Pa and 30 Pa between adjacent rooms. The required pressure depends on facility design, cleanroom classification, and regulatory requirements.

11. Can the AI-32 be connected to a Building Management System?

Yes. Although the AI-32 is a mechanical pressure switch rather than a transmitter, its electrical contacts can be connected to a Building Management System, PLC, alarm panel, or control system to indicate normal or alarm conditions.

12. Does the AI-32 require electrical power?

No. The sensing mechanism is entirely mechanical and does not require power to detect pressure changes. Electrical power is only required for the external device being switched, such as an alarm, relay, or controller.

13. Does the AI-32 require regular maintenance?

The AI-32 requires very little maintenance. During routine HVAC or cleanroom maintenance, it is recommended to verify the switching point and inspect the pressure tubing to ensure reliable operation.

14. What are the main applications of the AI-32?

The AI-32 is commonly used for:

• Cleanroom pressure monitoring
• HEPA filter monitoring
• Fan status monitoring
• Airflow proving
• Isolation room pressure control
• AHU filter monitoring
• Ventilation system alarms
• HVAC safety interlocks

15. Which industries commonly use the AI-32?

The AI-32 is widely used in:

• Pharmaceutical manufacturing
• Biotechnology facilities
• Hospitals
• Cleanrooms
• Laboratories
• Electronics manufacturing
• Food processing plants
• HVAC systems
• Medical device manufacturing

16. Which differential pressure switches can the AI-32 be used as a cross-reference for?

The AI-32 Differential Pressure Switch is suitable for applications with pressure ranges and switching characteristics similar to many commonly used differential pressure switches, including:

• Siemens QBM81 series (QBM81-3, QBM81-5, QBM81-10, QBM81-20)
• Dwyer ® 1910/1900 Series (1910-0, 1910-2, 1910-1, 1910-5, 1910-10, 1910-20)
• Johnson Controls P233A Series (P233A-4, P233A-10)
• Honeywell EDPS Series
• Honeywell DPS Series (DPS200, DPS400, DPS500, DPS1000, DPS2500)

Disclaimer : The comparisons above are cross-reference groupings based on overlapping pressure ranges and switching specifications. They are not direct or certified equivalence claims. Ace Instruments is an independent manufacturer and is not affiliated with, endorsed by Siemens, Dwyer ® Instruments, Johnson Controls, or Honeywell. Model numbers from those brands are used here purely for range-matching reference, not as interchangeability guarantees.

17. Why choose ACE Instruments?

ACE Instruments has more than 30 years of experience in manufacturing cleanroom monitoring and HVAC instrumentation. Our differential pressure products are trusted by pharmaceutical manufacturers, hospitals, and cleanroom integrators for their reliability, long service life, and dependable performance in critical applications.

18. How do I choose the right differential pressure switch?

The right pressure switch depends on the required switching pressure, HVAC application, filter pressure drop, cleanroom design, and control philosophy. Our application engineers can help you select the most suitable AI-32 model for pharmaceutical cleanrooms, hospitals, laboratories, isolation rooms, and HVAC systems.