ISO 20338:2019 | ORS
Oxygen Reduction Systems (ORS) for fire prevention - Design, installation, planning and maintenance
September 2019 | Edition: 1 | Licensed
Oxygen reduction systems (ORS) are designed to prevent fires from starting or spreading, by means of the introduction of oxygen reduced air and creating an atmosphere in an area which is having lower permanent oxygen concentration in respect to ambient conditions.
Oxygen reduction systems are not designed to extinguish fires.
The design and installation are based on detailed knowledge of the protected area, its occupancy and the materials in question. It is important to suit the fire protection measures to the hazard as a whole.
This document specifies minimum requirements and defines the specifications governing the design, installation and maintenance of fixed oxygen reduction systems with oxygen reduced air for fire prevention in buildings and industrial production plants. It also applies to the extension and modification of existing systems.
This document applies to oxygen reduction systems using nitrogen-enriched-air which are designed for continual oxygen reduction in enclosed spaces.
NOTE Nitrogen is, today, the most suitable gas to be used for oxygen reduction. For other gases, this document can be used as a reference.
This document does not apply to:
- oxygen reduction systems that use water mist or combustion gases;
- explosion suppression systems;
- explosion prevention systems, in case of chemicals or materials containing their own supply of oxygen, such as cellulose nitrate;
- fire extinguishing systems using gaseous extinguishing agents;
- inertization of portable containers;
- systems in which oxygen levels are reduced for reasons other than fire prevention (e.g. steel processing in the presence of inert gas to avoid the formation of oxide film);
- inerting required during repair work on systems or equipment (e.g. welding) in order to eliminate the risk of fire or explosion.
- explosion prevention systems, in case of chemicals or materials containing their own supply of oxygen, such as cellulose nitrate;
- fire extinguishing systems using gaseous extinguishing agents;
- inertization of portable containers;
- systems in which oxygen levels are reduced for reasons other than fire prevention (e.g. steel processing in the presence of inert gas to avoid the formation of oxide film);
- inerting required during repair work on systems or equipment (e.g. welding) in order to eliminate the risk of fire or explosion.
In addition to the conditions for the actual oxygen reduction system and its individual components, this document also covers certain structural specifications for the protected area.
The space protected by an oxygen reduction system is a controlled and continuously monitored indoor climate for extended occupation. This document does not cover unventilated confined spaces that can contain hazardous gases.
Note
I sistemi a Riduzione di Ossigeno (ORS) o a "deplezione d’ossigeno", sono dei metodi di protezione attiva di prevenzione degli incendi, basati sulla riduzione della concentrazione d’ossigeno presente nei locali protetti.
Questo tipo di sistemi sono sicuri e non nocivi per l’uomo. L’atmosfera ipossico che si realizza negli ambienti protetti con sistema a riduzione di ossigeno è equivalente, per il nostro organismo, alle condizioni dell’aria ad elevate altitudini.
L'amosfera ipossica, influisce sulla permanenza di un individuo, in particolare essa è dovuta a:
- percentuale di ossigeno residuo in ambiente;
- tempo di esposizione;
- sforzo legato all’azione da compiere;
- caratteristiche fisiche del soggetto;
- caratteristiche del locale (segnalazioni e vie d’esodo).
E' necessario garantire determinate misure di sicurezza in atmosfera sotto-ossigenata.
Il Documento al link sottostante tratta tali Sistemi in relazione alla 1a norma ISO in merito: ISO 20338:2019
Vedi il Documento: Sistemi a Riduzione di Ossigeno (ORS) ISO 20338:2019
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