Real-time Atmospheric Corrosion Sensor
ANSI/ISA 71.04-2013 monitoring for mission critical

ACM Corrosion Sensor

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key sensor features
A non-intrusive Plug & Play corrosion sensor for real time corrosion monitoring in mission critical. Equipment manufacturers (OEM) for mission critical infrastructure will typically specify the conditions in which systems can be used. It will be typically be mentioned as G1 - Mild. That standard is defined by the ISA 71.04 standard.

PCB corrosion Sensor features:
- measures corrosion level over time
- 2x 10cm probes: one for Copper (Cu), one for Silver (Ag)
- G1, G2, G3 or Gx classification based on 30 day interval period
- visual LED indication of corrosion severity
- design based on ANSI / ISA 71.04-2013 standard

- powered by the base unit.
- wired or optionally wireless.

- compact plug & play sensor.
- designed for indoor use.
- steel enclosure for non-power sensors or non-IP sensors. custom color & logo options available.
- industrial grade.
- 0u rack, DIN rail, magnetic or wall mountable sensor.
- plugs into the base unit.
- powered by the base unit (PoE, 12v DC, optionally 24v or -48v)
- alerts via SNMP Traps, email or SMS.
- out of the box integration via Modbus TCP, SNMP.
- optional integration via MQTT for Industrial IoT applications1New feature.
- optional integration via RS-485 enabling direct integration with your own gateway & controllers.2New feature

1Requires FW 10 or higher
2Some sensors are not available in RS-485 native versions. In that case RS-485 is available using the optional Modbus RTU module.
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ANSI / ISA Classification of Corrosion
Category Severy Copper Silver
G1 Mild <300 Å <200 Å
G2 Moderate <1,000 Å <1,000 Å
G3 Harsh <2,000 Å <2,000 Å
GX Severe >2,000 Å >2,000 Å
Equipment manufacturers (OEM) for mission critical infrastructure will typically specify the conditions in which systems can be used. It will be typically be mentioned as G1 - Mild. That standard is defined by the ISA 71.04 standard.

The sensor monitors for silver and copper corrosion and computes the severity over a rolling 30 days times frame.
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MTBF impacted by corrosion
Corrosion impacts the life span of critical equipment. That life span is expressed in MTBF or Mean Time Before Failure.

In some level of corrosion can reduce the life span by up to 25%. In severe corrosive environments, this increases to more than 75%.

This shows that uptime in mission critical is significantly impacted by the level of corrosion.
ISA Severity MTBF Reduction
G1 None
G2 up to 25%
G3 up to 50%
GX more than 75%
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Corrosion: an operation & capital risk
Risk loss benefit
In the above table we've seen the impact corrosion has on the life span of equipment in mission critical environments.

A reduced MTBF entails a significant OPEX and CAPEX risk:
- OPEX: corrosion will cause systems to fail resulting in business continuity being impacted
- CAPEX: equipment manufacturers will typically void warranty if damage is caused by corrosion
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Where does corrosion come from?
Electronic circuits use copper. Prior to RoHS, the exposed copper in electronics was soldered with lead protecting it against corrosion.

With the introduction of RoHS, lead could no longer be used and that protection is gone.

With the weakened protection of equipment due to RoHS, there are 4 main contributors to corrosion:
- temperature
- humidity
- air particles
- corrosive gasses

Monitoring for those risks with the right sensors enables you to put a corrosion risk mitigation strategy into place.
Corrosion sensor
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Recommended settings for G1 class environment
Risk Action Part number
Temperature Ideal temperature is 21°C (70F) with a ±1°C temperature change ENV-TEMP or ENV-THUM
Humidity rH should be below 55% and not change more than 6% per hour ENV-THUM
Air Circulation Air filtration and purification is paramount to keep corrosive contaminants out of the facility. Minimum 3 air changes per hour should be performed ENV-AIRPRESSURE or ENV-AIRFLOW
Particles Air particles from PM1 to PM10 should be kept below 70µg/m3. Particles larger than 1mm should be below 1,000µg/m3 ENV-PARTICLE or ENV-DUST
Corrosive Gasses Following limits in parts per billion (ppb) apply to mild environments:
H2S <3 ppb
SO2 <10 ppb
CL2 <1 ppb
NOx <50 ppb

HF <1 ppb
NH3 <500 ppb
O3 <2 ppb


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Why monitoring corrosion
in mission critical?
Corrosion is the degradation of materials due to a chemical reaction with their environment.

It can be a major issue in data centers, substations, electrical panels, switchgear and other mission critical infrastructure for several reasons:

Safety: Corrosion can compromise the structural integrity of the equipment, potentially leading to failure and posing a safety hazard to personnel.

Reliability: Corrosion can cause equipment to malfunction or fail, leading to downtime and reduced reliability.

Cost: Repairing or replacing corroded equipment can be costly. In addition, corrosion can reduce the efficiency of the equipment, leading to higher energy consumption and costs.

ne of the main benefits of real-time atmospheric corrosion monitoring using sensors is the ability to detect corrosion early, before it becomes a major problem. Sensors can continuously monitor the environment and alert maintenance staff when corrosion is detected, allowing them to take corrective action before the corrosion causes significant damage.

Real-time corrosion monitoring can also help to prevent equipment failures and downtime. If corrosion is allowed to progress, it can weaken structural components and cause equipment to fail, leading to costly repairs and lost productivity. By detecting corrosion early and taking preventive action, real-time corrosion monitoring can help to extend the life of equipment and reduce the risk of costly failures.

Real-time atmospheric corrosion monitoring using sensors is an important tool for maintaining the safety and reliability of data centers, substations, electrical panels, and switchgear.
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Source - International Society of Automation (ISA) - 71.04-2013