Permanent Outdoor Noise Monitoring Terminal

What is the Permanent Outdoor Noise Monitoring Terminal?

A weatherproof, continuously operating unit with a Class 1 or 2 microphone, telemetry and optional solar power for long-term noise monitoring at airports, construction sites, roads and industrial boundaries. It is the right choice for permit compliance and community complaint management.

Overview

The terminal combines an outdoor microphone with a rain cover, bird spikes and windscreen, an electrostatic actuator for automatic sensitivity checks, a signal processor, a data logger and communication modem in a pole-mounted or cabinet enclosure. It calculates Leq at intervals of one second to one hour and sends data to a web platform, where exceedance of a limit, for example 70 dB(A) daytime at a construction boundary, triggers SMS or email alerts. Audio recording of events helps attribute noise to sources. Weather sensors suppress invalid data during rain or high wind. Power comes from mains or from a solar panel and battery. Systems support continuous operation for years with annual calibration visits, and complete IEC 61672 compliance when equipped with Class 1 microphones.

How does it work?

A noise instrument converts sound pressure into an electrical signal with a calibrated condenser or MEMS microphone. The signal passes through frequency weighting filters, most commonly A-weighting that approximates human hearing, and C-weighting for peak and low-frequency content. A detector with exponential time weighting, Fast at 125 ms or Slow at 1 s, or an integrating stage produces the level in decibels relative to 20 µPa. Equivalent continuous level Leq, percentile levels such as L10 and L90, maximum and peak levels and sound exposure level are computed digitally. Class 1 instruments have tighter tolerances than Class 2 under IEC 61672-1. Octave or third-octave filter banks and FFT analysis add frequency information, and acoustic calibrators at 94 dB and 1 kHz check sensitivity. Permanent stations add weather protection and telemetry.

What are the key features?

• Automatic electrostatic actuator checks microphone sensitivity daily without site visits.
• Rain cover, bird spikes and windscreen protect the capsule during long outdoor use.
• Exceedance alerts by SMS or email support rapid response to noise complaints.
• Audio event recording helps identify sources such as machinery or aircraft.
• Weather sensors flag or suppress data taken during rain or high wind.
• Solar and battery option enables deployment where mains power is unavailable.

What are the technical specifications?

A typical permanent outdoor noise monitoring terminal configuration offers accuracy class of IEC 61672-1 Class 1 or 2, measurement range of 25–137 dB(A), logging interval of 1 s to 1 h, metrics of Leq, Lmax, L10, L50, L90, LN, self-check of Electrostatic actuator, daily and communication of 4G, Ethernet, RS-485. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Permanent Outdoor Noise Monitoring Terminal is used in construction site boundary monitoring, airport and road traffic noise, industrial fence-line noise and event and entertainment venue compliance. Across the wider Noise Monitoring class, laboratories also deploy it for community and environmental noise assessment, construction site noise compliance and occupational noise exposure surveys.

Which standards and certifications apply?

Relevant standards and methods include IEC 61672-1, IEC 61672-3, IEC 60942 (sound calibrators), ISO 1996-1, ISO 9612, IEC 61252 (personal exposure meters), GB 3096 and GB/T 3785.1. Certification candidates for this model are CE, China pattern approval and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Calibrate with an acoustic calibrator before and after each measurement session and record any drift, which should be under 0.5 dB. Use a windscreen outdoors, keep the microphone 1.2 to 1.5 m above ground and at least 3.5 m from reflecting surfaces for free-field environmental measurements, and avoid rain or condensation on the capsule. Record weather conditions because wind above 5 m/s invalidates many measurements. Instruments need periodic verification in an accredited laboratory, typically every one to two years, following IEC 61672-3. Store in dry conditions, replace batteries before long campaigns, and preserve raw time history when regulators may audit the data. Permanent stations require protection from birds, vandalism and lightning.

How do I select the right Permanent Outdoor Noise Monitoring Terminal?

Select a permanent terminal when noise must be tracked continuously with automatic alerts and audit logs. Handheld meters cost less but need an operator. In an RFQ, specify accuracy class, limit alarms, audio recording, communications, power and calibration interval.

How does it compare with other Noise Monitoring variants?

Choose the class and type according to the regulation: Class 1 for environmental noise assessment and legal evidence, Class 2 for general surveys and workplace screening. Decide between handheld meters for spot checks, dosimeters for worker exposure and permanent stations for continuous site monitoring. Check the level range, such as 20 to 140 dB, and whether the dynamic range covers both background and peak events. For industrial and product noise, frequency analysis in octave or third-octave bands is needed. Consider data storage, time-history logging with audio recording for source identification, IP rating, temperature range and battery life. For permanent installations, evaluate microphone protection, communication and power. Confirm that the supplier offers IEC 61672-3 periodic verification and traceable calibration.