Mine air pressure self-rescue device testing service

Mine Air Pressure Self-Rescue Device Testing Service – Comprehensive Evaluation of Respiratory Protection, Pressure Integrity and Functional Reliability for Chilean Mining Operations

As an ISO/IEC 17025 accredited independent testing laboratory, we offer specialised testing services for mine air pressure self‑rescue devices (also known as self‑contained self‑rescuers – SCSRs, and compressed‑air breathing apparatus – CABA) used in Chilean underground mining, tunnelling, and hazardous industrial environments. These critical safety devices provide breathable air to miners during emergency situations – including fires, explosions, toxic gas releases, and oxygen‑deficient atmospheres – enabling safe evacuation from the mine site. The performance, pressure integrity, and functional reliability of these devices are essential for protecting the lives of workers and for complying with Chilean mining safety regulations. Our test protocols evaluate the pressure‑holding capacity, breathing resistance, air flow rate, oxygen concentration (for O₂‑generating devices), carbon dioxide absorption efficiency, and mechanical durability of self‑rescue devices under simulated service and emergency conditions. All methods are aligned with ISO, EN, and ASTM standards, as well as Chilean regulations DS 132 (Safety regulations for mining operations) and NCh standards, including ISO 16900 (Respiratory protective devices – Methods of test), EN 137 (Self‑contained open‑circuit compressed air breathing apparatus), EN 400 (Self‑contained closed‑circuit breathing apparatus), ASTM F1766 (Standard Guide for the design, construction, and testing of self‑rescuers), and NCh 3002 (Respiratory protective devices – Self‑rescuers). Our inspection reports are recognised by the National Geology and Mining Service (SERNAGEOMIN), the Ministry of Mining, the Superintendency of Electricity and Fuels (SEC) (where electrical components are involved), and leading Chilean mining companies for equipment registration, safety compliance, and quality assurance.

Regulatory and Standardisation Framework for Self‑Rescue Devices in Chile

Chile has a robust regulatory framework for the safety of mining equipment, which includes strict requirements for self‑rescue devices:

• DS 132 – Safety Regulations for Mining Operations – Establishes the mandatory use of self‑rescue devices in underground mining and sets performance and maintenance requirements.
• SERNAGEOMIN – National Geology and Mining Service – The regulatory authority responsible for verifying compliance with DS 132 and approving self‑rescue devices for use in Chilean mines. SERNAGEOMIN requires that devices be tested and certified by accredited laboratories.
• NCh 3002 – Respiratory protective devices – Self‑rescuers – The Chilean standard that adopts and adapts international standards (ISO, EN) for self‑rescue devices used in the country.
• SEC – Superintendency of Electricity and Fuels – Regulates the electrical and compressed gas components of self‑rescue devices where applicable.
• ISO 16900 – Respiratory protective devices – Methods of test – The international standard for testing respiratory protective equipment, used as the reference for many Chilean mining safety requirements.
• EN 137 – Self‑contained open‑circuit compressed air breathing apparatus – The European standard widely adopted in Chile for compressed air self‑rescuers.
• EN 400 – Self‑contained closed‑circuit breathing apparatus – The standard for oxygen‑generating self‑rescuers.
• ASTM F1766 – Standard Guide for the design, construction, and testing of self‑rescuers – Used as a reference for testing protocols.
• Mining companies' internal specifications – Many large Chilean mining companies, including CODELCO, Antofagasta Minerals, and Anglo American, have additional requirements for self‑rescue device performance and testing, which we incorporate into our service.
• Application areas in Chile – Underground copper, gold, silver, and lithium mines in the northern regions (Atacama, Coquimbo, Antofagasta), as well as tunnelling projects for water and transport infrastructure.

Types of Self‑Rescue Devices and Components We Test

Our testing facilities and equipment are designed to accommodate a wide range of self‑rescue devices used in Chilean mining operations. Typical test articles include:

• Self‑contained closed‑circuit breathing apparatus (oxygen‑generating self‑rescuers) – also known as O₂ self‑rescuers, which generate oxygen through a chemical reaction (potassium superoxide). These are the most common type in Chilean mines.
• Self‑contained open‑circuit compressed air breathing apparatus (compressed air self‑rescuers) – equipped with a compressed air cylinder and a demand valve, providing a supply of clean breathing air.
• Combined or hybrid self‑rescuers – devices that combine both oxygen‑generating and compressed air capabilities.
• Filter self‑rescuers – devices that use a chemical filter to remove carbon monoxide and other toxic gases.
• Emergency escape hoods and hood‑type self‑rescuers – lightweight devices for quick deployment.
• Spare oxygen cartridges and chemical cartridges – for maintenance and replacement.
• Full‑face masks and mouthpiece assemblies – including the breathing tubes and valves.
• Harnesses, carrying cases, and storage containers – for assessing the durability and ease of deployment.

Pressure Integrity and Leakage Testing – Ensuring Air Tightness and Cylinder Integrity

• Hydrostatic pressure test for compressed air cylinders – ASTM E493 / ISO 9809 / NCh 3002 – For compressed air self‑rescuers, we test the air cylinders by filling them with water and applying a pressure of 1.5× the maximum operating pressure (typically 200‑300 bar) for a specified hold period. We measure the permanent expansion of the cylinder; an expansion greater than 5 % of the total expansion indicates a structural weakness. The cylinder is then inspected for leaks and visual deformation. This test is mandatory for the re‑certification of compressed air cylinders in Chilean mines.
• Pneumatic leak test – ISO 16900 / EN 137 / NCh 3002 – We pressurise the complete self‑rescue device (including the breathing circuit, valves, and connections) with dry air or nitrogen to the rated pressure. We measure the pressure decay over a specified period (typically 5‑30 minutes). A pressure drop exceeding the allowable limit (typically 2 % of the test pressure) indicates a leak. We also use a soap‑solution bubble test to locate the leak source. The allowable leakage rate is typically ≤ 0.1 mL/min for high‑quality self‑rescuers.
• Helium leak test – ASTM E493 / ISO 20486 – for ultra‑sensitive leak detection – For critical components and for devices that require the highest level of integrity, we use a helium mass spectrometer to detect micro‑leaks down to 10⁻⁸ std cm³/s. This test is especially important for oxygen‑generating self‑rescuers, where any leakage could lead to premature depletion of the oxygen supply.
• Valve and seal integrity test – ISO 16900 / EN 137 – We test the sealing performance of the breathing valve, the exhalation valve, and the pressure‑relief valve under a range of pressure conditions. The test measures the leakage rate through the valve when it is closed. A leakage rate > 0.5 L/min (for exhalation valves) is considered a failure.
• Oxygen cartridge or chemical cartridge integrity test – EN 400 / NCh 3002 – For oxygen‑generating self‑rescuers, we test the integrity of the chemical cartridge (potassium superoxide) by checking for any leaks or damage to the cartridge casing, and by testing the seal between the cartridge and the breathing circuit. We also measure the moisture content of the chemical cartridge; a moisture content > 5 % can reduce the oxygen‑generating efficiency.

Breathing Resistance and Air Flow Testing – Evaluating Ease of Breathing

• Inhalation and exhalation resistance test – ISO 16900 / EN 137 / NCh 3002 – We mount the self‑rescue device on a breathing simulator (or a mechanical lung) that mimics human breathing patterns. The simulator applies a specified breathing rate and tidal volume (e.g., 20 breaths/min, 2 L/breath for a 40 L/min ventilation rate). We measure the pressure drop during inhalation and exhalation. The inhalation resistance must be ≤ 2.5 mbar (at 40 L/min) and the exhalation resistance ≤ 2.0 mbar (at 40 L/min) for most self‑rescuers. Higher resistance can cause breathing difficulty and premature exhaustion.
• Air flow capacity test – ISO 16900 / EN 137 – We measure the maximum air flow rate that the self‑rescue device can deliver. For compressed air self‑rescuers, we measure the flow rate through the demand valve at a specified cylinder pressure (e.g., 150 bar). The flow rate must be ≥ 200 L/min (for open‑circuit devices) to ensure an adequate supply during high‑exertion activities.
• Oxygen concentration test (for O₂‑generating self‑rescuers) – EN 400 / NCh 3002 – We measure the oxygen concentration in the breathing gas during a simulated breathing cycle. The oxygen concentration must be ≥ 21 % (for open‑circuit devices) or ≥ 95 % (for closed‑circuit devices) to ensure that the user receives an adequate oxygen supply. A drop in oxygen concentration below the allowable limit indicates that the chemical cartridge is exhausted or defective.
• Carbon dioxide absorption efficiency test – EN 400 / NCh 3002 – For closed‑circuit self‑rescuers (which recycle exhaled air), we measure the efficiency of the carbon dioxide (CO₂) absorption system (e.g., soda lime). We introduce a known concentration of CO₂ (typically 3‑5 %) into the breathing circuit and measure the CO₂ concentration at the inhalation port. The CO₂ concentration must be ≤ 1.5 % (at a ventilation rate of 40 L/min) to prevent hypercapnia.
• Breathing resistance after cartridge activation – for oxygen‑generating self‑rescuers – We activate the oxygen cartridge and measure the inhalation and exhalation resistance immediately after activation and after 10 minutes of simulated breathing. The resistance must remain within the specified limits.

Mechanical Durability and Deployment Testing – Simulating Field Conditions

• Drop impact test – ISO 16900 / EN 137 / NCh 3002 – We drop the self‑rescue device (in its carrying case) from a specified height (typically 1.0‑1.5 m) onto a steel or concrete surface to simulate an accidental drop during storage or handling. We then test the device for any damage, leakage, or loss of function. The device must remain operational after the drop test, with no visible cracks or damage to the case, cylinder, or breathing circuit.
• Vibration and shock test – IEC 60068‑2‑6 / IEC 60068‑2‑27 / NCh 3002 – We subject the self‑rescue device to a defined vibration profile (5‑500 Hz, 1‑2 g acceleration) and mechanical shock (e.g., 20‑50 g, 10‑20 ms duration) to simulate the transport and handling conditions in Chilean mines. After the test, we measure the pressure integrity and breathing resistance. A failure is indicated by leakage, loosening of the internal components, or a change in the breathing resistance.
• Pull‑out and deployment test – ISO 16900 / NCh 3002 – We simulate the deployment of the self‑rescue device from its storage location, measuring the force required to remove the device from its case or bracket. The device must be easily accessible and require no more than 50 N of force to remove. We also measure the time required to don the device (from storage to ready‑to‑breathe) and ensure it is within the specified limit (typically ≤ 20 seconds).
• Harness and strap tensile test – ASTM D5034 / ISO 13934‑1 / NCh 3002 – We test the tensile strength of the harness, straps, and buckles used to secure the self‑rescue device. The straps must withstand a tensile force of at least 1 000 N without breaking or slipping. This test is essential for ensuring that the device remains securely attached to the user during evacuation.
• Corrosion resistance testing – ASTM B117 / ISO 9227 / NCh 3002 – For metallic components (cylinders, valves, buckles), we expose the self‑rescue device to a salt spray environment (5 % NaCl, 35 °C) for 240‑500 hours to simulate the corrosive conditions of Chilean coastal mines and humid environments. After exposure, we inspect for any corrosion that could affect the integrity or operation of the device.

Simulation of Extreme Climatic Conditions – Atacama Desert, Patagonia and High Altitude

• High‑temperature operation test – for simulating the Atacama Desert – We condition the self‑rescue device at 40 °C, 50 °C, and 60 °C for 24‑48 hours, and then test the pressure integrity, breathing resistance, and deployment time. The device must remain functional at 60 °C, as temperatures in the Atacama Desert can exceed 40 °C during the day.
• Low‑temperature operation test – for simulating the Patagonia and the Andes – We condition the device at -10 °C, -20 °C, and -30 °C for 24 hours, and then test the breathing resistance and pressure integrity. The breathing resistance must remain within the specified limits at low temperatures.
• High‑altitude pressure test – for simulating mining operations at 3 000‑5 000 metres above sea level – We perform the pressure integrity and breathing resistance tests in a low‑pressure chamber that simulates altitudes of 3 000, 4 000, and 5 000 metres above sea level. The device must maintain its pressure and breathing performance at these altitudes.
• Humidity and condensation test – for simulating coastal and southern Chilean climates – We condition the device at 40 °C and 95 % RH for 48 hours, and then test the breathing resistance and the performance of the chemical cartridge (for O₂‑generating devices). The moisture should not cause the chemical cartridge to prematurely activate or degrade the CO₂ absorption efficiency.
• Thermal cycling test – for simulating diurnal and seasonal temperature variations – We subject the device to 20‑50 thermal cycles between -20 °C and +60 °C, and then perform the full range of functional tests. The device must pass all tests after thermal cycling.

End‑of‑Service‑Life and Durability Testing – Assessing Long‑Term Reliability

• Accelerated ageing test – ASTM F1766 / ISO 16900 / NCh 3002 – We expose the self‑rescue device to a temperature of 70 °C and 95 % RH for 168 hours to simulate long‑term ageing. After ageing, we test the pressure integrity, breathing resistance, and oxygen generation efficiency. A loss of more than 10 % in oxygen generation capacity or a pressure drop of more than 2 % indicates a failure.
• Oxygen cartridge shelf‑life test – for oxygen‑generating self‑rescuers – We perform a chemical analysis of the oxygen‑generating material (potassium superoxide) to determine its remaining capacity. The oxygen generation capacity (in litres of O₂ per gram of cartridge) is measured, and the remaining shelf‑life is estimated. The cartridge must retain at least 90 % of its original capacity after 5 years of storage.
• Breathing cycle endurance test – ISO 16900 / EN 400 – We run the self‑rescue device on a breathing simulator for the full rated duration (typically 15, 30, or 60 minutes) at a specified ventilation rate (e.g., 40 L/min). We measure the oxygen concentration, CO₂ concentration, and breathing resistance at regular intervals to ensure that the device can provide the required performance for the entire rated period.
• Repeated deployment and storage test – for assessing the impact of repeated handling – We deploy and repack the self‑rescue device 50 times, and then test the breathing resistance, pressure integrity, and deployment time. The device must remain functional after repeated deployment cycles.
• Acoustic emission testing – ASTM E569 / NCh 3002 – We monitor the self‑rescue device during the pressure and cycling tests for acoustic emissions that could indicate crack initiation or propagation in the cylinder or the breathing circuit.

Interpretation of Results and Acceptance Criteria

• Leakage rate (mL/min) – A leakage rate ≤ 0.1 mL/min is excellent ; between 0.1 and 0.5 mL/min is acceptable ; > 0.5 mL/min is insufficient.
• Inhalation resistance (mbar at 40 L/min) – ≤ 2.5 mbar is excellent ; between 2.5 and 3.5 mbar is acceptable ; > 3.5 mbar is insufficient.
• Exhalation resistance (mbar at 40 L/min) – ≤ 2.0 mbar is excellent ; between 2.0 and 3.0 mbar is acceptable ; > 3.0 mbar is insufficient.
• Oxygen concentration (%) – For closed‑circuit devices, ≥ 95 % is excellent ; between 90 and 95 % is acceptable ; < 90 % is insufficient. For open‑circuit devices, ≥ 21 % is required.
• CO₂ concentration at inhalation port (%) – ≤ 1.5 % is excellent ; between 1.5 and 2.0 % is acceptable ; > 2.0 % is insufficient.
• Deployment time (seconds) – ≤ 20 seconds is excellent ; between 20 and 30 seconds is acceptable ; > 30 seconds is insufficient.
• Statistics and uncertainties – For each series of tests (at least 5 devices), we provide the mean, standard deviation, and coefficient of variation (CV) for each parameter. A CV < 5 % is considered excellent.

Compliance and Certification – Supporting SERNAGEOMIN and Mining Industry Requirements

Chile has a strict regulatory and safety system for mining equipment, including self‑rescue devices, involving several institutions and technical standards:

• SERNAGEOMIN – National Geology and Mining Service – The regulatory authority that verifies compliance with DS 132 and approves self‑rescue devices for use in Chilean mines. SERNAGEOMIN requires that devices be tested by accredited laboratories (ISO/IEC 17025) and that the test results be submitted as part of the device registration.
• DS 132 – Safety Regulations for Mining Operations – Establishes the mandatory use, maintenance, and testing of self‑rescue devices in underground mining.
• SEC – Superintendency of Electricity and Fuels – Regulates the electrical and compressed gas components of self‑rescue devices where applicable.
• NCh 3002 – Respiratory protective devices – Self‑rescuers – The Chilean standard that adopts international standards (ISO, EN) for self‑rescue devices.
• ISO 16900 – Respiratory protective devices – Methods of test – The international standard for testing respiratory protective equipment.
• EN 137 – Self‑contained open‑circuit compressed air breathing apparatus – The European standard widely adopted in Chile for compressed air self‑rescuers.
• EN 400 – Self‑contained closed‑circuit breathing apparatus – The standard for oxygen‑generating self‑rescuers.
• ASTM F1766 – Standard Guide for the design, construction, and testing of self‑rescuers – Used as a reference for testing protocols.
• Application areas in Chile – Underground copper, gold, silver, and lithium mines in the northern regions (Atacama, Coquimbo, Antofagasta), as well as tunnelling projects for water and transport infrastructure.

Advantages of Our Service for the Chilean Market

• ISO/IEC 17025 accreditation – guaranteeing the reliability, traceability, and international acceptance of our results.
• Bilingual reports (English/Spanish) – to facilitate submissions to Chilean authorities and international partners.
• Simulation of extreme climatic conditions – our tests integrate the effects of high solar radiation (Atacama Desert), low temperatures (Patagonia and the Andes), high humidity (coastal and southern regions), and high altitude (Andean mines).
• Support for SERNAGEOMIN certification – our reports are directly usable for SERNAGEOMIN device registration and certification.
• Experience in the mining and energy sectors – our laboratory has extensive experience in the key sectors of the Chilean economy, particularly copper and lithium mining.
• Adapted turnaround times – we understand the logistical and commercial constraints of the Chilean market and are committed to delivering results within competitive timeframes.

Conclusion

The testing of mine air pressure self‑rescue devices is a fundamental safety tool for guaranteeing the protection of workers in Chile's demanding mining environments. Our testing services, accredited under ISO/IEC 17025 and compliant with the requirements of SERNAGEOMIN, DS 132, and NCh 3002, allow you to validate the pressure integrity, breathing performance, and functional reliability of your devices, optimise their selection, and ensure regulatory compliance. Whether you are a manufacturer, importer, mining company, or safety engineer, we accompany you in the mastery of self‑rescue device performance, from initial testing to final certification.