Isolated compressed oxygen self-rescue device testing service

Isolated Compressed Oxygen Self-Rescue Device Testing Service – Comprehensive Evaluation of Respiratory Protection, Pressure Integrity and Operational Reliability for Chilean Mining and Underground Operations

As an ISO/IEC 17025 accredited independent testing laboratory, we offer specialised testing services for isolated compressed oxygen self-rescue devices (also known as self-contained self-rescuers – SCSRs, or closed-circuit oxygen breathing apparatus) used in Chilean underground mining, tunnelling, and hazardous industrial environments. These critical safety devices provide a supply of breathable oxygen to workers during emergencies – including fires, explosions, toxic gas releases, and oxygen‑deficient atmospheres – enabling safe evacuation from the mine. Unlike compressed air devices, isolated compressed oxygen self-rescuers recycle exhaled breath by removing carbon dioxide and adding oxygen from a compressed oxygen cylinder or a chemical oxygen-generating cartridge, providing a longer duration of protection (typically 15-60 minutes). 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, oxygen delivery rate, breathing resistance, carbon dioxide absorption efficiency, mechanical durability, and deployment performance 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 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, and leading Chilean mining companies for equipment registration, safety compliance, and quality assurance.

Regulatory and Standardisation Framework for Isolated Compressed Oxygen 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.
• 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.
• ISO 16900 – Respiratory protective devices – Methods of test – The international standard for testing respiratory protective equipment.
• EN 400 – Self‑contained closed‑circuit breathing apparatus – The European standard for oxygen‑generating and compressed oxygen self‑rescuers, widely adopted in Chile.
• 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 have additional requirements, 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 Isolated Compressed Oxygen 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:

• Closed-circuit oxygen self-rescuers with compressed oxygen cylinders – devices that store oxygen in a high‑pressure cylinder (typically 200‑300 bar) and regulate its delivery to the user.
• Closed-circuit oxygen self-rescuers with chemical oxygen‑generating cartridges – devices that generate oxygen through a chemical reaction (potassium superoxide) and are activated by the user’s breath.
• Combined or hybrid self-rescuers – devices that combine both compressed oxygen and chemical oxygen‑generating capabilities.
• Emergency escape hoods and mouthpiece assemblies – including the breathing tubes, valves, and face masks.
• Oxygen cylinders and valves – including the pressure regulator and the demand valve.
• Carbon dioxide absorption cartridges (soda lime or other CO₂ absorbents) – used to remove exhaled CO₂ from the breathing circuit.
• Cooling systems for the breathing circuit – to reduce the temperature of the inhaled oxygen.
• Harnesses, carrying cases, and storage containers – for assessing the durability and ease of deployment.

Pressure Integrity and Leakage Testing – Ensuring Oxygen Retention and Circuit Integrity

• Hydrostatic pressure test for oxygen cylinders – ASTM E493 / ISO 9809 / NCh 3002 – We test the oxygen 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 oxygen cylinders in Chilean mines.
• Pneumatic leak test – ISO 16900 / EN 400 / NCh 3002 – We pressurise the complete self‑rescue device (including the oxygen cylinder, 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 400 – We test the sealing performance of the oxygen delivery 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.

Oxygen Delivery Performance – Evaluating Oxygen Concentration, Flow Rate and Duration

• Oxygen concentration test – EN 400 / NCh 3002 – We measure the oxygen concentration in the breathing gas during a simulated breathing cycle using a breathing simulator (or a mechanical lung) that mimics human breathing patterns. The oxygen concentration must be ≥ 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 oxygen cylinder is depleted, the chemical cartridge is exhausted, or there is a malfunction in the delivery system. The test is performed at a ventilation rate of 40 L/min (or as specified) for the full rated duration of the device (15, 30, 45, or 60 minutes).
• Oxygen flow rate test – ISO 16900 / EN 400 – We measure the oxygen flow rate delivered to the user at different points during the simulated breathing cycle. The average oxygen flow rate must be sufficient to maintain the required oxygen concentration at the specified ventilation rate. The flow rate must be ≥ 1.5 L/min (for devices with a demand valve) or ≥ 2.0 L/min (for continuous flow devices).
• Oxygen cylinder pressure and duration test – EN 400 / NCh 3002 – We measure the pressure in the oxygen cylinder at the start of the test and at regular intervals during the simulated breathing cycle. The pressure must remain above the minimum operating pressure (typically 50 bar) for the entire rated duration. We also measure the total oxygen consumption (in litres) for the full rated duration. The device must provide the specified oxygen supply for the full rated duration (e.g., 15 minutes for a 15‑minute device, 60 minutes for a 60‑minute device).
• Oxygen purity test – ISO 16900 / EN 400 – We analyse the oxygen delivered to the user for impurities (e.g., nitrogen, carbon dioxide, moisture). The oxygen purity must be ≥ 99.5 % for medical‑grade oxygen cylinders, or ≥ 95 % for chemical oxygen‑generating systems.
• Temperature of inhaled oxygen – EN 400 / NCh 3002 – We measure the temperature of the inhaled oxygen at the mouthpiece or face mask. The temperature must not exceed 50 °C (for short‑duration devices) or 40 °C (for long‑duration devices) to prevent thermal injury to the user.

Carbon Dioxide Absorption Efficiency – Ensuring Safe CO₂ Levels

• CO₂ absorption efficiency test – EN 400 / NCh 3002 – We introduce a known concentration of CO₂ (typically 3‑5 %) into the breathing circuit at the exhalation port and measure the CO₂ concentration at the inhalation port (after passing through the CO₂ absorption cartridge). The CO₂ concentration must be ≤ 1.5 % (at a ventilation rate of 40 L/min) to prevent hypercapnia. The test is performed for the full rated duration of the device. A CO₂ concentration > 2.0 % is considered a failure.
• CO₂ absorption cartridge capacity test – EN 400 / NCh 3002 – We measure the total CO₂ absorption capacity of the cartridge (in grams of CO₂ per gram of absorbent) by determining the mass gain of the cartridge during the CO₂ absorption test. The cartridge must have sufficient capacity to absorb the CO₂ produced during the full rated duration (e.g., 15 minutes, 30 minutes, or 60 minutes). A low capacity indicates that the cartridge is exhausted or defective.
• Moisture content of the CO₂ absorbent – EN 400 / NCh 3002 – We measure the moisture content of the CO₂ absorbent (soda lime or other absorbent) before and after the test. A moisture content < 15 % (or > 20 %) can reduce the absorption efficiency. The moisture content must be within the specified range.
• Breakthrough time of the CO₂ absorbent – EN 400 / NCh 3002 – We measure the time from the start of the CO₂ introduction until the CO₂ concentration at the inhalation port exceeds the allowable limit (1.5 %). The breakthrough time must be ≥ the rated duration of the device (e.g., 60 minutes for a 60‑minute device).

Breathing Resistance and Mechanical Comfort – Evaluating Ease of Breathing

• Inhalation and exhalation resistance test – ISO 16900 / EN 400 / NCh 3002 – We mount the self‑rescue device on a breathing simulator that 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.
• 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.
• Air flow capacity test – ISO 16900 / EN 400 – We measure the maximum air flow rate that the self‑rescue device can deliver at the specified ventilation rate. The flow rate must be ≥ 200 L/min to ensure an adequate supply during high‑exertion activities.
• Cooling system performance – EN 400 / NCh 3002 – For devices with a cooling system (e.g., a heat exchanger or a cooling jacket), we measure the temperature of the inhaled oxygen at the mouthpiece during the simulated breathing cycle. The temperature must remain below the allowable limit.

Mechanical Durability and Deployment Testing – Simulating Field Conditions

• Drop impact test – ISO 16900 / EN 400 / 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 cylinder shelf‑life test – for compressed oxygen self‑rescuers – We perform a hydrostatic test and a visual inspection of the oxygen cylinder to ensure it is safe for continued use. The cylinder must be re‑tested every 5 years, as required by Chilean regulations.
• 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.

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.
• Oxygen concentration (%) – ≥ 95 % is excellent ; between 90 and 95 % is acceptable ; < 90 % 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.
• 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.
• 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 400 – Self‑contained closed‑circuit breathing apparatus – The European standard for oxygen‑generating and compressed oxygen 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 isolated compressed oxygen 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, oxygen delivery 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.