The interview with the Mozzanica's Technical Director, Mario Mignacca on oxygen reduction technologies continues.

The following questions delve into technical, design, regulatory, and insurance-related aspects, as well as human health implications.


What are the redundancy requirements of an oxygen reduction fire protection system?

A fire protection system must never fail, so it is crucial to over-design the nitrogen production—since a machine might need maintenance without necessarily breaking down—and ensure the introduction of nitrogen into the protected environment remains constant. This value may change over time due to variations in material movements (especially in automated warehouses).

A full warehouse is different from an empty one because the available volume of air naturally varies depending on the amount of stored goods.

It also depends on the type of goods stored; if there is a change in the type of products, it will be necessary to assess whether they can be introduced into the protected area without compromising the system's ability to prevent fires.

The design of an oxygen reduction fire protection system must continue to evolve based on the customer's needs, the characteristics of the building enclosure, the intended use, and the materials present in the protected premises.


What are the main design requirements of an oxygen reduction fire protection system?

Designing an oxygen reduction fire protection system starts with the composition of the natural atmosphere, which contains 21% oxygen. The natural atmosphere is considered "polluted" with oxygen, so the system must compensate by producing nitrogen, which can range from 99% pure nitrogen to 98%, 95%, etc., depending on the system design and the desired regulation speed.


The detection of gases within an environment protected by an ORS is mandated by regulations: why?

Gas detection within the oxygen-reduced environment is crucial, especially for managing the distribution of nitrogen within the environment. Regulatory requirements mandate a minimum number of oxygen sensors to be deployed/distributed/allocated. It is the responsibility of the design team to strategically place these sensors to ensure there are no anomalies in their distribution, particularly near specific points (within enclosed spaces, false ceilings, sub-floors, ducts, near walls and doors, etc.). These points are critical not only for nitrogen distribution but also because they could lead to the dissipation of oxygen that has remained "trapped".


Why is it required to have a smoke detection system in an environment protected by an oxygen reduction system?

While the standard merely recommends smoke detection, it is crucial within an oxygen-depleted environment because smoldering fires could develop that are not detected by oxygen sensors, as these cannot distinguish between oxygen and carbon monoxide.

Choosing smoke detection compliant with UNI 9795 or other relevant standards is a decision for the designer, but the system should be distinct from gas detection.

An alternative approach could be to use predictive thermographic systems in combination to detect the heat from the initial stage of a fire. Nonetheless, the predominant risk arises from electrical system malfunctions.


The target concentrations in a room protected by an ORS depend on the stored materials; what is the state of the art, particularly regarding what is established by UNI 16750?

The current standard UNI EN 16750 is still evolving because there are several aspects that can be improved, especially concerning target concentrations. There are ongoing discussions on the possible need to lower target concentrations; however, this would reduce the possibility of personnel spending time in these areas (there are already time limitations in place). There is still ongoing debate regarding monitoring systems for concentrations, distribution systems, and the accreditation of maintenance entities. The standard is under revision to try to incorporate all the necessary variables.


From your privileged point of view, what do you see regarding regulatory developments and the market for oxygen reduction systems for fire prevention purposes?

I clearly see an interest in the ORS market niche and the potential to extend fire prevention beyond just protection. Regulatory developments vary across international standards. The UNI team has participated in the European community working group, and UNI 16750 is now an EN standard. However, there is strong international skepticism within the ISO realm; some member states, such as Japan and Australia, oppose adopting the standard due to its perceived conflict with their stringent occupational health and safety regulations, particularly concerning workers entering environments with less than 18% oxygen.


What are the qualification requirements for suppliers of an oxygen reduction system?

Today, the qualification of suppliers for an oxygen-reduced environment does not have defined regulatory requirements. To produce and design an oxygen reduction system, there is no need for specific requirements other than being fire protection technicians, that is, suppliers of fire protection equipment. Several competitors are entering the market, but to ensure a sufficiently high-quality service, they must have a solid corporate structure and strong engineering capabilities. The quality requirements set by a certification body could serve as a reference model to regulate the access of qualified entities on the market.


What role do insurance companies play in the development of oxygen reduction fire protection technology?

Insurance companies play a fundamental role in the development of any fire protection technology. We've seen this with sprinklers; maybe we'll see it with oxygen reduction systems as well. The key is to convey that with this system, property can be effectively protected at the source, rather than waiting for a fire to occur. The critical role of professionals is to strengthen the credibility of these applications through solid designs and a strong regulatory framework backing them.


Let’s now shift our attention to the occupants. What training and requirements must individuals have when entering work environments protected by oxygen reduction systems?

The training of personnel entering work environments protected by oxygen reduction systems is a crucial step because the personnel will be exposed to oxygen levels different from atmospheric norms. The UNI EN 16750 standard provides reference timelines and methods for entering oxygen-reduced environments. In particular, care must be taken to prevent occupants from coming into contact with "pockets" of nitrogen that may stagnate within protected environments due to stratification caused by temperature differences. In fact, the regulation assumes that the nitrogen introduced dissipates uniformly within the protected area, which may not always be the case. Designers must plan for ventilation systems to aid convective movements inside protected environments. Ventilation of these spaces is a fundamental concept that needs to be introduced in a standard, and the UNI and ISO working groups are actively gathering the necessary experience and case studies to develop regulations (which are still in the early stages of implementation).


A worker within an environment protected by an oxygen reduction system faces the risk of hypoxia. What is it, and what are the warning signs and symptoms?

Oxygen is absorbed by the lungs because the pressure inside the alveoli is lower than the air pressure at sea level.

In conditions of oxygen deficiency, the warning signs are lightheadedness, headache, dizziness, nausea, and lack of appetite.

The first consequence is that the brain suffers from a relative loss of mental clarity.  The initial symptoms can be compared to a drunken state; as these initial symptoms worsen, balance issues, headaches, and the sensation of vomiting occur.

If the symptoms worsen, this is the sign that one should move to an environment with normal oxygenation.


And what approach should one take?

The progression of hypoxia symptoms in an oxygen-reduced environment is relatively slow because acute suffocation conditions do not occur. However, there is an adaptation phase that has its limits, and if the situation worsens, the person will start feeling confused, have reduced motor coordination, and find it difficult to perform even simple actions (progressively, of course). From the first signs of discomfort, depending on the amount of oxygen available, the worsening can be more or less rapid, but in any case, the person has time to take action, primarily by returning to an environment with normal oxygen levels. It is difficult to imagine sudden acute effects unless the person has pre-existing conditions identified during the preliminary fitness assessment.


What behavioral norms should be observed within an environment protected by an ORS system to counteract the effects of hypoxia?

Behavior within a hypoxic environment differs from that in a situation with normal oxygen levels. One precaution is to increase hydration because consuming liquids helps to thin the blood. One of the human body's adaptations to oxygen deficiency is an increase in cardiac output, as the body enlarges red blood cells in search of oxygen, elevating hematocrit and consequently thickening the blood. Drinking plenty of fluids helps to thin the blood and reduce symptoms. Another rule is to listen to one's body and never exert oneself excessively. Workers in under-oxygenated environments can slow down if they feel out of breath; initially, it may take a little time to return to normal, but as adaptation sets in, just a few seconds are sufficient.


What are the eligibility criteria for access for workers in environments protected by oxygen reduction systems?

The proper use of ambient oxygen requires healthy lungs capable of taking in oxygen from the surrounding environment, adequate cardio-circulatory activity to distribute it, and a sufficient quantity of hemoglobin in the blood to transport oxygen from the lungs to the tissues.

Therefore, severe lung diseases that impair proper oxygen diffusion at the alveolar level, blood disorders characterized by reduced hemoglobin (such as anemias or alterations in hemoglobin's chemical characteristics), and cardiac or cardiovascular conditions where the heart lacks adequate efficiency to handle exertion, are all contraindications for suitability to enter under-oxygenated environments.

These health conditions are critical considerations for any work activity that demands physical exertion, but they become significantly more important in conditions of reduced oxygen availability. Standard assessments (such as spirometry, blood tests including a complete blood count, and cardiac evaluation with resting and possibly stress electrocardiography) are sufficient as an initial step to evaluate suitability. Physical fitness is certainly important for individuals engaging in non-work activities at altitudes with low oxygen, whereas specific physical preparation for workers is not strictly necessary.


The ORS regulations have focused more on fire prevention aspects than on worker safety, leaving these aspects to be covered by the general occupational health and safety regulations; what is your opinion?

The protection of workers' health and safety is very important, and if perhaps at the regulatory level it has been somewhat overlooked due to the lack of specific guidelines, the principle of utmost caution must be applied. The employer has a moral obligation to implement preventive and evaluative initiatives to achieve the highest standard of caution and to ensure that workers are protected.


From an occupational medicine perspective, how do traditional confined spaces differ from environments where low oxygen concentration is maintained for fire prevention?

The difference between a confined space in the traditional sense and working environments with low oxygen concentration is fundamental. In traditional confined spaces, we don't know what might happen; we have a number of unknown elements. In environments where an oxygen reduction system is present and operational, we know what the atmospheric composition will be, so the level of uncertainty is minimized. Although the regulations still need improvement, there are currently some established guidelines for safeguarding health in this context.


Is it necessary to use a self-contained breathing apparatus (SCBA) to enter an environment protected by an oxygen reduction system?

The use of SCBAs is obviously necessary when the percentage of oxygen is very low; below 15% concentration, problems can already occur. Even a person in the best possible condition might have difficulty functioning for extended periods in such an environment. It is also important to consider the length of time spent in an under-oxygenated environment. For short periods, significant consequences are not expected, but if the length of time increases, the use of SCBAs may be necessary.


We mentioned that smoldering fires can occur in an environment protected by an oxygen reduction system; what health risks can arise in terms of occupational health? And what precautions should be taken?

Combustion in the presence of a low percentage of oxygen is a serious problem because CO is produced instead of CO2 under these conditions. In an environment protected by an oxygen reduction system, this is an event that cannot be 100% ruled out. In such cases, the person may not be aware of what is happening, leading to significant CO intoxication and potential loss of consciousness without the ability to take conscious action to oppose it. If it is expected that such types of combustion could occur, a technical device to monitor CO levels would be necessary.



Mario Mignacca

Technical & Marine Director

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