Method instructions in fire extingushing systems

1. In 1978, 24 countries (including USSR) signed Montreal Protocol as per ozone destroying substances. In 1993, in Bangkok at the summit conference of Montreal Protocol participants with Russia taking part in the conference as a USSR inheritor, there was made a resolution to cease production of 13b1, 12b1, and -114b2 fire extinguishing chladones excluding certain agreed quantity of chladones produced for the most important objects.

2. Chladone 114b2 is the basic gas for fire extinguishing in Russia. Technical Committee on Alternative Substances backed Russia request as per permitted yearly quota for production of chladone 114b2. But, the permission is normally to be given for one one only, which means possible rejection of such Russia request for permission in the future.

3. Problems of usage of alternative substances instead of ozone destroying chladones (114b2, 13b1 etc) are of State importance, which is proved by Russian Government Decree No. 526 dated May 24, 1995 that specifies solutions for the whole complex of problems, including rejection of fire ozone dangerous extinguishing substances for ozone friendly ones, working out normative documents, state standards and products certification.

4. The recommendations specify general requirements and substitution routine of ozone destroying chladones for ozone friendly substances in fire extinguishing systems at the particularly important enterprises, either in function or under reconstruction.

5. The recommendations are exclusively applicable for automated gas fire extinguishing systems mounted at the objects of particular importance that contains chladones 114b2 and 13b1.

6. The recommendations have been elaborated in Russia specialized research institute of Ministry of Home Affairs by V. Karpov, A. Lagozin, V. Nikolayev, V. Nekrasov, A. Ponomaryev, V. Strogonov with assistance of representatives of First Department of State Fire Extinguishing Systems of Ministry of Home Affairs N. Toshchev, V. Matsidon and V. Olkhovikov.

114b2 chladone (tetra fluorine dibromine ethane - C₂F₄Br₂) at normal conditions is a heavy colorless liquid with specific smell, inertly flammable. Chladone 114b2 is a strong inhibitor for hydrocarbon fuels combustion and highly effective fire extinguisher. Upper and lower concentration limits of spreading of chladone vapors flames aren’t available in the air, while in oxygen - 28-54%. Temperature of combustion of vapor blends 450 ^°С, temperature of spontaneous combustion in the air - 580 ^°С. 114b2 chaladone reacts with alkaline and solkali micro dispersed metals.

Vapours belongs to 4 danger class. Density _р.з = 1000 mg/m³. For basic physical and chemical properties of chladone 114b2 please refer to the table 1 (see below).

13b1 Chladone (bromine three fluorine methane) - CF₃Br is a colorless gas without smell, non-conductor that easily liquefied under slight pressure. It is a strong fire inhibitor. It is kept liquefied in balloons. Temperature of spontaneous combustion - 695 ^°С; concentration limits of spreading flames in the air and oxygen are unavailable, it has relatively limited toxicity. Density _рз= 30 000 mg/m³, vapors belongs to 4 danger class.

For basic physical and chemical properties of 13b1 chladone please refer to the table 1 (see below)

RECOMMENDATIONS FOR SUBSTITUTION OF OZONE DESTROYING CHLADONES IN FIRE EXTINGUSHING SYSTEMS AT PARTICULARLY IMPORTANT OBJECTS FOR ALTERNATIVE OZONE FRIENDLY SUBSTANCES

1. While substituting ozone destroying chladones (114b2 and 13b1) and chemical compositions of "3,5" type at automated gas fire extinguishing systems (AGFES), the concept as follows should be observed:

• 13b1 chladone is to be substituted after guarantee period of usage and storage at AGFES(Ch) (or in reserves) as it has got not Russian certificates;
• chladone 114b2 is to be substituted or regenerated after guarantee period of usage and storage at AGFES(Ch) (or in reserves). In case of chladone regeneration, its period of usage at AGFES(Ch) is permitted to be extended after fire-extinguishing efficacy of the regenerated substance has been proved.

Basing on the State standard Р 50291-92.1 (Technical Conditions for chladone 114b2), shelf life of chladone 114b2 in balloons of fire-extinguishing systems is 15 years, and 10 years for chladone 13b1, basing on the US standard NFPA 12A and Technical Conditions 6-02 - 1104-87.

For the newly designed AGFES, chladone 114b2 is not permitted for usage basing on the regulating norm 22-96 and amendments to it.

2. General requirements to automated gas fire extinguishing systems while substituting ozone destroying chladones.

2.1. Necessity in AGFES and exact type of gas fire extinguisher composition are to be conditioned upon permissible level of fire safety system at the object with fire spreading speed at the initial stage, economical expediency of the installation usage and tactic potentialities of fire-brigades taken into account.

2.2. Design, mounting, reconstruction and exploitation of AGFES are to be performed in conformity with valid norm and technical sheets.

2.3. Installation is to function safe either in regular mood of the object operation or in case of an accident.

2.4. Installation is to be adequately filled with fire extinguishing substance.

2.5. Installation is to be safety in function for servicing employees and those who work in a protected area.

2.6. Operation of electrical units in AGFES is to correspond to fire and inflammation category of the protected premises.

2.7. AGFES is to secure formation of command impulse:

• for automated turn-off of ventilation and isolation of doorways to interconnecting rooms before fire extinguisher is out in protected premises;
• for self-closing door;
• for alarming and precautionary signals to light and sound switch boards;
• for delaying installation operation until people evacuation, but lo less then for 30 sec.

2.8. Alarming notice at light boards "Gas-escape!" and sound signal are to be insured inside protected premises. At the entrance into protected premises, light signal "Gas-no entry!" is be insured, and in orderly personnel guard-room - appropriate signal for outing fire extinguishing substance is to be insured.

2.9. Installation is to be equipped with manual start button:

• remote - from the units located at the entrance into protected area, and if needed, from fireman station;
• local - from the units located in fire extinguishing stations, or from units located in start/stop switch board.

2.10. Manual starts buttons of the installation are to be secured against their accidental putting into operation and mechanical damage and located out of potential flame.

2.11. Gas fire extinguishing installation is to be equipped with extinguisher weight control system or pressure control system (with gas extinguishers).

2.12. Gas extinguishing compositions in AGFES are to have certificate of compliance and fire safety certificate.

3. Recommendations as per fire extinguishers for substitution of chladone 114b2 and chemical composition of "3,5" type.

3.1. As potentially permitted ozone friendly fire extinguishers substituting ozone destroying chladones (114b2, 13b1 and composition of "3,5" type) in fire extinguishing automated installations of the objects of particular importance, substances as follows can be recommended for usage:

• carbonic acid СО₂,
• 125 and 318C chladones;
• gas SF₆,
• nitrogen N₂;
• argon Ar,
• blends of inert gases (compositions such as "Argonite", "Inergen").

For basic characteristics of the gas compositions above please refer to the table 2 (see below).

3.2. Mass of gas fire extinguishing blends (GFEB) in one 40 liters balloon is to total no less then (kg):

• carbonic acid СО₂ - 25 ±0,1;
• 125 chladone C₂F₅H - 35 ±0,1;
• 318С chladone C₄F₈H - 47 ±0,1;
• gas SF ₆ - 40 ±0,1;
• argon Ar - 10 ±0,2;
• nitrigen N₂ - 7 ±0,1.

3.3. Calculations of the required mass of GFEB is to be made in accordance with methods described in regulating norm 22-96.

3.4. Time of outing of calculated mass of GFEB in protected area should not exceed limits as follows:

• for fuel materials with normative volume fire extinguishing concentration С_н < 20%:

t = 10 sec for modular AGFES;
t = 15 sec for centralized AGFES;

• for fuel materials with normative volume fire extinguishing concentration С_н > 20%:

t = 30 sec for modular AGFES;
t = 60 sec for centralized AGFES.

3.5. Norms for fire extinguishing concentrations of the GFEB base on regulating norms 22-96, or to be proven by tests in compliance with regulating norms 51-96.

3.6. When filling AGFES with regenerated chladones, document proves of their fire extinguishing concentration in conformity with methods described in regulating norms 51-96 are to be provided.

3.7. When substituting ozone destroying fire extinguishing chladones (114b2 and 13b1 and composition of "3,5" type) required mass of ozone friendly extinguisher is to be proven by calculation.

3.8. For modular AGFES, 100% of GFEB, available at enterprise's stock house for sufficient protection of the largest room, is s must.

3.9. For AGFES with centralized storage of GFEB, 100% reserve of GFEB kept in reserve balloons of AGFES is a must.

3.10. GFEB outing time is to be proven by calculation or experimentally, using GFEB or analogical substances.

CONCLUSIONS

1. Researches made it evident that direct substitution of ozone destroying chladones in fixed gas fire extinguishing installations is impossible due to increased number of balloons for GFEB and also changes in the network of distributing pipe lines for creating adequate conditions for GFEB supplies to protected area.

2. Substitution of ozone destroying chladones in fire extinguishing installations at the objects of particular importance is to be performed in accordance with specially designed program that was made basing on examinations and tests of specific AGFES(Ch) and with present recommendations and other regulating norms taken into account. At that, the concepts as follows are to be observed:

2.1. AGFES using "3,5" composition are to be substituted immediately due to the toxicity of the composition and also lack of valid regulating norms specifying its usage.

2.2. 13b1 chladone is to be substituted at AGFES for other fire extinguishing substances after guarantee period, as it is subject to limited usage in compliance with regulating norms of other countries and has got no Russian certificates.

2.3. Chladone 114b2after expiration in AGFES is to be gradually substituted for another fire extinguishing substances.

2.3.1. Substitution of chladone 114b2 in AGFES at objects of particular importance (00B) is to be performed little by little depending on the consumption of existing reserves and strictly observing measures for elimination of its non-sanctioned escape and pollution of the environment.

3. Present reformation and re-orientation of number of 00B objects, updating of old enterprises and introduction of new technologies (for instance, microprocessors, PC, automated databases so on) provide new opportunities for implementation of fire extinguishing systems at the objects and enterprises. Currently, main trend is wide usage of modular gas fire extinguishing installations, for which now certified equipments are produced and regulating norms as per their design and application have been elaborated.

4. Basing on the work done, there is a conclusion as follows:

• substitutions of ozone destroying chladones in AGFES is a complex and composite problem, which is now can not be resolved in general for various classes of flames;
• as possible and potential ozone friendly fire extinguishing substances to substitute ozone destroying chladones (114b2, 13b1 and "3,5" composition) in automated installations of AGFES at objects of particular importance, can be recommended as follows:

carbonic acid СО₂;
125 chladone C₂F₅H;
gas SF₆;
Argon Ar;
Nitrogen N₂;
blends of inert gases (compositions like "Argonite", "Inergen");
combination of various fire extinguishing compositions.

5. Exact option of fire extinguisher for substitution of ozone destroying chladones in AGFES of specific objects is to be made basing on scrupulous and detailed analysis of volume planned solutions of the protected area, specific features of technological process, level of inflammation, efficiency and tactic and technical details of the fire extinguishing installations, as well as economical expediency of usage of a certain fire extinguisher.

Table 1 Physical and chemical properties of chladones 114b2 and 13b1

Table 2 Physical and chemical characteristics of ozone friendly GFEB