TERA System for Regulating Radon Concentrations in Buildings

The TERA systems allow measuring and regulating radon concentration in residential spaces. Radon measuring probes distributed in a building transmit the current radon concentration values to the actuator. If the set values are exceeded, the actuator will switch the air-conditioning unit (fan) and ensures that the contaminated spaces will be vented. The TERA regulating systems represent cheap and energy-saving nondestructive solution of monitoring and curative anti-radon action not only for existing buildings.


TERA Wireless Regulating System


Radon measuring probes located in building transmit their current radon concentration values to central unit wirelessly. Central unit analyzes this information and on the basis of measured (set) concentration level value it sends command to actuator (wireless actuator or actuator in central unit can be use) which is hardwired with power relay. Power relay switches on a fan which decreases radon concentration within an area. After decreasing of radon concentration, actuator receives command to switch off fan. This cycle repeats depending on increasing or decreasing volume activity of radon in building. If the radio signal strength between individual elements is insufficient, a repeater must be used to extend the signal.

connection of regulating system TERA


TERA regulating system elements

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Basic technical parameters:

Average measurement sensitivity 0,25 count/hour/Bq.m-3
(method RaA+RaC; 15°C ÷ 30°C; rel. hum. 20% ÷ 40%)
Measuring range MDA – 10E6 Bq/m3;
MDA = 100 Bq/m3 per 1 hour or 20 Bq/m3 per 24 hours
Measurement uncertainty < 13% at 300 Bq/m3 per 1 hour;
< 3% at 300 Bq/m3 per 24 hour
Measurement algorithm slower, more sensitive (calculated from RaA+ RaC)
quicker, less sensitive (calculated from RaA)
Radon concentration results display short-term (1 hour running average)
long-term (24 hours running average)
Measuring relative humidity range 10 – 90 %
Measuring temperature range -20 to + 60 °C
Measuring barometric pressure range (terminal unit only) 150 – 1150 hPa
Radio interface 868MHz
Max number of measuring network elements 16 (probes,actuators,repeaters)
Probe to terminal unit distance (RF range) depends on the number of walls and building material, up to 600 m in open space
The possibility of using the repeater for the RF range extending yes
The connection between the terminal unit and the control element (relay) wired / wireless
Alarm threshold adjustable, default 200 Bq·m-3
Results reading interval (terminal unit) 240-65535 sec (4 min - 18.2 hours)
Records saving interval (probe) 1- 255 minutes, default 1 hour
Results memory capacity in terminal unit 100 days (1 probe,1 hour records)
Results memory capacity in probe 150 days
System life without charging > 1 year
Maximum switching power (central unit, actuator) 30 W DC (1A/30V)
Maximum switching power (power relay) 1500 VA AC (6A/250V)

Documents to download:

pdf TERA leaflet

Other tools:

RadonView – PC application for easy viewing of measuring radon records and spectrums from SURO(NRPI)


Sales Support:
Josef Heřman, +420 266 107 356, +420 737 047 377, herman.josef@tesla.cz

Technical Support:
Ing. Václav Řeřicha, +420 266 107 650, rericha.vaclav@tesla.cz

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