Challenges in Domestic Production of Firefighting Pressure Sensors

Firefighting pressure sensors are critical sensing elements in fire protection systems, directly affecting the reliability and response speed of automatic sprinklers, fire pump activation, and pipeline pressure monitoring. In high-rise buildings, industrial plants, and data centers, failure to detect abnormal pressure promptly can delay firefighting or cause system failure. Historically, China has relied heavily on imported high-precision, high-reliability pressure sensors, especially for micro-differential, high differential pressures, and extreme environment specifications, with imported products dominating the market.

Recently, the government has strongly promoted domestic sensor production. Policies like the "Three-Year Action Plan for Smart Sensor Industry" have identified high-precision MEMS pressure sensors as a key area for breakthroughs. By 2026, domestic chip self-sufficiency has increased from less than 5% to over 15%, with market expansion continuing. However, compared with international standards, domestic firefighting pressure sensors still face multiple challenges in accuracy, stability, overpressure tolerance, and process maturity. Nexisense, specializing in industrial and firefighting sensors, offers high-reliability firefighting pressure transmitters through independent R&D and process optimization, helping users achieve stable monitoring and domestic substitution. This article analyzes core issues and potential solutions in the domestic development process.

Piezoresistive Pressure Sensors: Current Status and Main Pain Points

Piezoresistive sensors, with mature technology and relatively controllable cost, are widely used in firefighting applications. Most domestic manufacturers use imported piezoresistive chips with self-designed signal conditioning circuits and transmitter housings, achieving "semi-domestic" solutions. This pragmatic approach exposes several structural issues.

Firstly, high sensitivity to temperature and humidity. The piezoresistive effect relies on silicon strain properties and is significantly affected by environmental temperature changes. Zero drift and sensitivity temperature coefficients are relatively high. In fire pump rooms or outdoor pipelines, temperatures can range from -20℃ to 60℃ with significant humidity variations. Without adequate compensation, piezoresistive sensors may drift, causing false alarms or missed events.

Secondly, static pressure characteristics depend on process quality. Errors, linearity, and repeatability depend on silicon diaphragm etching, doping uniformity, and packaging. While domestic processes have improved, they still lag behind leading international companies, particularly under high static pressure where nonlinear errors are larger.

Finally, limited overpressure tolerance. Firefighting systems often face water hammer and instantaneous high pressure. Piezoresistive diaphragms are thin, typically tolerating only 2–5× full scale, making them vulnerable. Nexisense has optimized piezoresistive products for firefighting scenarios, using enhanced compensation circuits and thicker diaphragms to improve temperature stability and overpressure tolerance, suitable for fire pump outlets and pressure stabilization points.

Capacitive Pressure Sensors: Technical Advantages and Domestic Challenges

Compared with piezoresistive sensors, capacitive sensors have inherent advantages in accuracy, long-term stability, low power consumption, and overpressure tolerance. Measurement is based on diaphragm displacement causing capacitance change, with no current through the sensitive element. Temperature coefficients are over ten times lower, and overpressure tolerance can exceed 100× rated pressure, ideal for the high reliability requirements of firefighting systems.

However, capacitive sensors are highly dependent on manufacturing processes. Silicon-based capacitive sensors require precise silicon-glass anodic bonding, vacuum cavity packaging, and thin-film suspension MEMS processes, with many key technologies historically restricted abroad. Domestic manufacturers have made progress over years, producing silicon capacitive sensors whose accuracy and static pressure characteristics closely approach imported products, though long-term stability is still slightly inferior.

Developing high differential and micro-differential specifications is another bottleneck. Firefighting pipelines require monitoring small pressure changes (0.1–1 kPa) to detect leaks or blockages. Capacitive sensors must achieve high sensitivity and signal-to-noise ratio in this range. Domestic products still face gaps in noise suppression and parasitic capacitance control.

Nexisense continues investing in capacitive technology, combining advanced MEMS processes with proprietary ASIC compensation chips, offering high-precision series suitable for firefighting micro-differential monitoring, significantly narrowing the gap with imports.

Special Requirements for Firefighting Pressure Sensors and Domestic Breakthrough Directions

Firefighting systems require high-reliability pressure sensors (MTBF>100,000 hours), fast response (<10ms), water hammer and vibration resistance, wide operating temperature, and EMC compatibility. Imported products excel in these metrics but are expensive, have long lead times, and pose supply chain risks.

Domestic development must focus on:

• Process and equipment dependence: High-end lithography, etching, and bonding equipment still rely on imports; accelerating domestic substitution is essential.

• Material and packaging consistency: Silicon wafer quality, thin-film stress control, and vacuum stability directly affect long-term drift.

• Compensation algorithms and calibration technology: Intelligent temperature compensation and multi-point nonlinearity correction improve accuracy.

• Reliability verification systems: Establish long-term aging and shock testing standards aligned with firefighting certifications (e.g., CCC, UL).

Positive signals: By 2026, multiple companies have achieved full MEMS domestic production, with increasing chip self-sufficiency. Nexisense firefighting products have passed numerous reliability tests, suitable for sprinklers, fire pump rooms, and pipeline pressure stabilization.

Trends: Accelerated Transition from Following to Competing

Looking forward, domestic firefighting pressure sensors will evolve toward intelligence and integration. Digital transmitters supporting Modbus RTU and 4–20mA HART will become mainstream. Edge computing functions will enable anomaly warnings and predictive maintenance. Integration with IoT platforms will support remote diagnostics and data traceability.

Policy support, including the "14th Five-Year Plan for Smart Sensors" and smart firefighting requirements by the Ministry of Emergency Management, will further accelerate domestic substitution. By 2030, the domestic rate for high-reliability firefighting pressure sensors is expected to exceed 70%.

FAQ: Common Questions on Domestic Firefighting Pressure Sensors

Why are capacitive sensors more suitable for high-reliability firefighting?
Low temperature coefficient, strong overpressure tolerance, and long-term stability make them ideal for low false alarm, maintenance-free requirements.

Why do piezoresistive sensors still rely on imported chips?
While mature, piezoresistive diaphragms require high-precision doping and etching. Domestic consistency and yield still lag behind.

How can domestic sensors improve temperature stability?
Using multi-point temperature compensation algorithms, SoI silicon materials, and precise calibration significantly reduces zero and sensitivity drift.

What overpressure capacity is required in firefighting systems?
Sensors must withstand water hammer, typically ≥20–50× rated pressure; capacitive sensors are advantageous.

Conclusion

Domestic development of firefighting pressure sensors has made notable progress, but piezoresistive environmental sensitivity, capacitive process thresholds, and micro-differential development remain key bottlenecks. Given the zero-tolerance requirement of fire safety, technological breakthroughs and reliability verification are urgent. Local brands like Nexisense are bridging the gap through independent chip development, advanced compensation technologies, and rigorous testing, providing high-performance, stable, cost-effective domestic solutions.

Driven by policy and market demand, domestic firefighting pressure sensors are moving rapidly from “usable” to “excellent.” Choosing suppliers with full-chain independence and deep experience in firefighting scenarios will be crucial for protecting lives and property. Domestic substitution is not just about cost—it is about safety and autonomous control.