GOST 53325 New version. New requirements.

GOST 53325 New version. New requirements.

GOST 53325 New version. New requirements

The adoption of Federal Law No. 123-FZ «Technical Regulations on Fire Safety Requirements» in 2008 fundamentally changed the structure of the main regulatory documents in the field of fire safety, the basis of which before the law was put into effect was fire safety standards (FSB). The main provision regulating the need to replace the regulatory framework was the content of paragraph 3 of Article 4 of the law, which states that «regulatory documents on fire safety include national standards, codes of practice containing fire safety requirements.»

Thus, the developers of regulatory documents were faced with the task of creating new documents in the shortest possible time, the provisions of which would form the basis for fulfilling the requirements of the law. Of course, this was not about simply revising the names of regulatory documents. The NBPs developed in the late 90s — early 2000s were technically and morally obsolete by the end of the first decade of the 21st century, since the provisions of the law on Technical Regulation did not allow changes to be made to the standards since 2003. As a result, the possibility of using advanced technologies and new technical solutions was blocked by the requirements of the old regulatory framework.

Why and who needed it is not for us to discuss. As it usually happens, the task of developing a new regulatory framework was set suddenly and such a short time was allocated for its implementation that it was impossible to do this work efficiently and without errors. Of course, over the years of inactivity, the developers of regulatory documentation had accumulated a lot of blanks that needed to be updated with the regulatory framework, which was done as far as possible. However, the national standards and codes of practice that appeared did not become the standard of regulatory creativity. Considering the above, as well as the truth that regulatory documents affecting technical issues should be adjusted at least once every 2-3 years (after all, science and technology do not stand still), there was a need to revise a number of standards, one of which is GOST R 53325-2009 “Firefighting equipment. Technical means of fire automation. General technical requirements. Test methods”.

This GOST has incorporated technical requirements and testing methods for most devices and instruments that are part of fire automatic systems: fire detectors, alarms, control and monitoring devices, control devices and uninterruptible power supplies for technical means of fire automatic systems, thus combining a series of previously existing fire safety standards.

The main impetus for revising GOST was an attempt to introduce into it the most logical provisions introduced into international and European standards. Despite the persistent desire of standard-setters to harmonize domestic regulatory documents with international ones as much as possible, the method of direct translation of EN 54 and ISO 7240 standards, as was done in Ukraine, was rejected as unacceptable. The main reasons for the illogicality of the complete introduction of international standards in Russia are, firstly, the presence of a domestic system of views and requirements for technical means of fire automatics that has been established for decades, and secondly, the imperfection of international standards.

At the same time, international standardization committees have done significant work in recent years to consolidate in the regulatory framework very important provisions, the adoption of which in domestic standards is advisable.

The changes introduced into the draft of the new edition of GOST affected three main areas: 

• fire tests of fire alarms, including within the framework of certification;
• requirements for manual fire alarms;
•  requirements for fire control and monitoring devices and control devices.

As follows from the currently valid version of GOST, fire tests during certification procedures are mandatory only for flame detectors. Heat and smoke fire detectors are tested on special laboratory stands «HEAT» and «SMOKE» channels, respectively.

During these tests, all the main environmental parameters are standardized: temperature and its growth rate, air flow speed and direction, growth rate of optical density of the environment, and the nature of the flammable load. Naturally, the test conditions created in the stand only indirectly simulate the impact of fire factors on the detectors, and the testing process itself can be defined as «instrumental». The objective of fire tests is to attempt to simulate the conditions of a real fire and evaluate the response of fire detectors to the combustion of various types of flammable load.

During fire tests, fire detectors, depending on the factor they control (temperature, smoke, electromagnetic radiation of the flame), are exposed to fire factors created during the combustion of various materials: wood, cotton fabric, polyurethane foam, flammable liquids burning with smoke emission (n
Heptane), and flammable liquids burning without smoke emission (ethyl alcohol). The type and quantity of combustible load are standardized. Tests are conducted in a room measuring 10x7x4 m. The combustible load is placed in the center of the room on the floor, and the detectors are installed in the ceiling area, which is a fragment of a circle with a radius of 3 m, the projection of the center of which is located at the location of the test source. Measuring instruments are also mounted in this area (Fig. 1). The procedure and criteria for conducting fire tests are probably not worth describing. All this information is provided in the regulatory documentation.

The issue of the advisability of introducing fire tests into the scope of certification tests may cause a discussion. It should be noted that fire tests are very expensive and require significant time expenditures. Positive results of tests on laboratory stands, although not in full, but all
they confirm the quality characteristics of the detector and allow us to create a general idea of ​​the meaning, stability and repeatability of the characteristics of the detectors produced.

In addition, the common opinion that fire tests of point optical-electronic smoke detectors allow us to determine their selective sensitivity to smoke of various natures can be criticized. Indeed, as a method of detecting smoke, almost all of these detectors use the effect of scattering and reflection of optical radiation by smoke particles. Considering that silicon semiconductor devices generating optical radiation in the near IR range are most often used as an optical pair, the sensitivity of detectors to smoke will depend only on the design of the detector and on the parameters of the electronic circuit, which is fully verified during tests on a laboratory bench. This means that if one detector is twice as sensitive as another to smoke from one test source, then the ratio of sensitivities to smoke from another test source for these detectors will remain approximately the same.

Why then increase the volume of certification tests, and therefore their duration and, most importantly, the price?

If we talk about the selective sensitivity of detectors to smoke of various nature, then, as stated above, for point smoke detectors with a traditional silicon optoelectronic pair, the results of fire tests are essentially predetermined. It can be said that the sensitivity of a single-spectrum point smoke detector is characterized by the reflectivity of smoke particles of a specific nature for a given wavelength of optical radiation. However, the manufacturer can use not only silicon semiconductors, and if we look at the problem even more broadly, it should be noted that two-spectrum devices have begun to appear on the smoke detector market, for example, BOSCH detectors with an additional «blue» LED. In this case, the results of fire tests cannot be predicted and the features of such detectors can only be identified during fire tests. This is due to the fact that the reflectivity of smoke particles, depending on their «color» and size, is also largely determined by the wavelength of optical radiation. For such detectors, fire tests can be fully considered as tests to determine the selective sensitivity of smoke detectors to smoke of various natures.

However, the main answer to the question of the advisability of conducting fire tests may be the results of comparative tests conducted by the fire automation department of the Federal State Institution VNIIPO of the Ministry of Emergency Situations of Russia with a number of point smoke fire detectors.

All detectors were preliminarily tested in the laboratory stand «SMOKE CHANNEL» and showed positive results, first of all, in terms of sensitivity, which for all detectors, as specified in the regulatory documents, was in the range from 0.05 to 0.2 dB/m. From the series of detectors, detectors with high sensitivity (0.073-0.10 dB/m) and less sensitive (over 0.10 dB/m) were selected. It should be noted that a smoldering cotton wick was used as a smoke source during testing on the laboratory stand. During fire tests with test source TP 3 (smoldering cotton), i.e. with smoke of the same nature, the response time of the detectors did not correlate with sensitivity. Some detectors with lower sensitivity responded earlier than highly sensitive ones. When the detectors were exposed to the combustion of the test source TP 5 (n-Heptane), the highly sensitive detectors were the first to respond. What is the reason for such strange behavior of the detectors? In fact, there is nothing surprising in the discrepancy between the sensitivity parameters and the response time. The detection ability of smoke detectors is greatly affected by the aerodynamic properties of the detector's smoke chamber design. In the laboratory stand, the detector is exposed to a flow of smoky air, the direction (parallel to the plane of the detector's attachment) and the speed of which (about 0.2 m/s) are strictly regulated. In the fire test chamber, the direction and speed of the air flow are determined by the combustible load itself. The TP 3 source creates a very weak convective flow, as a result of which smoky air enters the smoke chamber with low aerodynamic indicators extremely slowly.

High combustion energy of the TP 5 source, on the contrary, contributes to the creation of a strong convective flow, providing sufficient air mass movement speed at the location of the detectors. Obviously, less sensitive detectors, which responded faster to the combustion of the TP 3 source, have a more advantageous smoke chamber design for the conditions of detecting a real fire. Thus, the sensitivity value of the detector obtained during laboratory tests cannot form the basis for the criterion for selecting a detector for a specific facility with a specific combustible load. Of course, not every designer is so conscientious that before choosing the type of detectors to protect the facility, he will thoroughly study all possible documentation based on the results of fire tests (unfortunately, very often the main criterion for choosing a detector is its price).

In order to simplify the selection procedure, detectors are classified by detection capability (three classes) for each type of flammable load after fire tests. Even a novice designer can apply such information.

So, doubts about the advisability of conducting fire tests have been largely dispelled, but is it necessary to conduct these tests as part of certification? After all, the purpose of periodic certification tests of detectors is to confirm the stability of their production, which is fully verified as part of tests on laboratory benches. The new version of GOST R 53325 gives a clear negative answer to this question, but on the condition that fire tests have been conducted and information on their results is available. The manufacturer can conduct fire tests once in any accredited testing laboratory that has the necessary test bench, or during the first certification procedure of the detector. In other words, the results of fire tests obtained after the detectors have been put into production are valid for the entire period of their production.

During re-certification tests, fire tests are not carried out, except in cases where the manufacturer makes changes to the design or circuit of the detectors that could affect the results of the fire tests.

The next technical device, the requirements for which have been significantly expanded in the new version of the standard, is a manual fire alarm. The new requirements mainly affected the design and appearance of manual alarms. A manual fire alarm is perhaps the only technical device included in automatic fire alarm systems that can be interacted with by a person who has no relation to the system. At the same time, this element can be used to activate the system at the earliest stage of fire development, when automatic alarms are not yet able to detect the fire. Based on this, the appearance of a manual fire alarm should be as unified as possible. Strict requirements for the design and appearance of hand alarms have long been prescribed in European and international standards, and some manual alarms produced and used in Russia still look like either a doorbell button or an elevator call button.

When forming the requirements for manual call points introduced into the new version of the standard, the requirements of ISO and EN standards were taken as a basis (90 percent). The logic behind introducing these requirements is that manual call points are truly general-purpose products. Their appearance should clearly indicate their functional purpose, and the method of activating them should not cause difficulties even for a person who has seen a manual call point for the first time, and even in a stressful situation.

In addition to making changes to the design requirements, again with the aim of harmonizing with international standards, it was necessary to increase the regulated values ​​of the forces applied to the drive element of the fire alarm, made in the form of a button or lever. The previously valid requirement for the insensitivity of such an alarm to a force of less than 5 N and the mandatory transition to alarm mode at a force of more than 15 N has been changed. Now the limits of force application are determined by the values ​​of 15 and 25 N, respectively.

In international and European standards, the force that must be ignored by a manual call point is set at 25 N, regardless of the type of the drive element (a fragile breakable element or a button). The call point must be activated by striking a special test ball with an impact energy of at least 0.29 J. This parameter is checked during tests of manual call points, including certification tests. Thus, at present, the requirements for manual call points with a fragile element, prescribed in domestic and international standards, coincide, and for call points with a push-button drive element, they differ significantly. As a result, foreign manufacturers exporting their products to the Russian market are forced to make changes to the design of push-button call points supplied to Russia in order to reduce the required applied force. The new version of the standard will partially eliminate this problem, although, as can be seen from the above, the limiting force value is 25 N, at which the detector should not operate according to international standards, but should operate according to the new version of our GOST.

In our opinion, increasing the value of the limit force applied to the push-button element of the manual alarm above 25 N is not entirely logical, and testing the operation of alarms with a push-button drive element by hitting it with a test ball is not entirely correct. After all, the button is not hit — it is pressed, which means that the effect is achieved by applying force, and not a force impulse.

The next section of the GOST, which has undergone significant changes, defines the requirements for fire-fighting devices and their components. In the process of developing the changes, first of all, an attempt was made to eliminate the dual interpretation of the provision on automatic integrity control of communication lines through which devices interact with peripheral devices. Integrity control of wired fire alarm loops, carried out by control and monitoring devices, does not surprise anyone, since manufacturers are accustomed to the mandatory fulfillment of this requirement. For quite a long time, regulatory documents reflected the requirement for mandatory integrity control of communication lines with actuators of automatic fire extinguishing systems, such as pyropatrons, valves. The appearance in 2009 in the text of the standard of a requirement for control devices on the need to ensure automatic integrity control of communication lines with «… actuators of fire protection systems and technical means that record the operation of fire protection equipment …» was perceived ambiguously.

Fire alarm control and monitoring devices with an output for connecting an alarm device, made in the form of an ordinary «dry» relay contact, are still circulating on the Russian market, and the manufacturer, who is told that GOST does not allow such a solution, since the line is not monitored, is surprised and even indignant, considering this requirement excessive. Of course, ensuring automatic control of the integrity of communication lines requires the use of special technical solutions in the circuitry of devices, which leads to a slight complication, and therefore an increase in the cost of devices, but we must not forget that we are dealing with a security system, the task of which is to protect people and material assets from fire.

After all, if the communication line with the same alarm is broken, it will not work, which means that people will not be informed of the danger in a timely manner. If the automatic fire extinguishing system is working at the same time, an additional danger to a person may be the lack of information about the imminent release of a fire extinguishing agent (for example, gas).

A broken (or shorted) circuit of the valve position limit switch will cause a failure in the fire extinguishing system algorithm. A broken circuit of the door position sensor in a gas or aerosol fire extinguishing system will allow the release of an expensive fire extinguishing agent in an open room, which means that extinguishing will not be carried out.
There are a great many such examples, and the question as a whole is purely rhetorical: «How can a security system fail to secure its operation?» Stop saving on your own security. It is necessary that the circuits of each sensor and each actuator that influences the algorithm of the fire protection system be monitored for integrity, and this provision must be normatively fixed in the documents.

A particularly «thrifty» (or rather lazy) manufacturer may object, saying that the system's performance may be impaired if any of the device's units fails, so what now, monitor each unit. The answer is simple. It won't make things worse. Equipment with self-monitoring functions has always been more reliable.

Another thing is that increasing the reliability of equipment by providing self-monitoring and, even more so, redundancy of components does lead to a significant increase in the cost of equipment and is not always economically feasible. The use of technical solutions that allow for monitoring the integrity of communication lines does not increase the cost of equipment so much, and given that a violation of the integrity of wire communication lines (especially a break) is much more likely than a failure of the equipment itself, this requirement must be met.

It should be noted that the new version of the GOST still allows not to perform integrity testing of wire communication lines for short circuits, as a less probable phenomenon than a break, for power supply circuits of actuators with a voltage of over 150 V and for control circuits of pyropatrons.

The active resistance of the pyropatron is so small that, taking into account the active resistance of the cable wires, the difference between the normal state of the wire line and a short circuit in the cable is practically imperceptible. The cost of units that allow detecting a short circuit in a power cable with a sufficiently high voltage is already far from cheap, therefore, given the low probability of a short circuit in a powerful power cable, the requirement for detecting a short circuit in it has the status of a recommended one.

The requirements of the standard for displaying information by devices have also undergone significant changes. In the currently valid version of the standard, the requirements for indication devices are essentially reduced to the need for their presence. As a result, there are devices on the market whose indications can only be quickly identified by a person who knows the device intimately and has worked with it for many days. An untrained operator, upon hearing an audio signal, will spend more than one minute deciphering the message, which is unacceptable in an alarm situation.

In the new version of the standard, the requirements for indication and signaling are very strict and at first glance may seem excessive, but they are quite feasible. The incentive to write these requirements were the provisions of ergonomics and ease of perception of information generated by the device, the reliability of its display, as well as all the same issues of harmonization with international standards.

The new version of GOST regulates the mandatory presence of generalized single indicators of the main events, such as, first of all, «Fire», «Malfunction», «Start». Decoding of events by type and direction is allowed to be carried out by means of both individual single indicators and means of displaying text and symbolic information, for example, LCD displays, plasma panels, etc.

Such indication allows the operator to instantly assess the situation, determining the nature of the event, and to quickly obtain information about the direction of the event without using the device controls intended for such purposes as, for example, “scrolling” the screen.

Many manufacturers of fire-fighting devices, especially those who use components of various controllers as hardware, may have a negative attitude towards the mandatory requirement to use single indicators as generalized ones, citing the fact that various types of displays allow simulating such an indicator directly on the screen. This is certainly possible, however, firstly, the glow of a single indicator is perceived by the operator much more clearly than a symbol on the display, and does not depend on the “window” displayed by the display, and secondly, the reliability of a single indicator is significantly higher than the reliability of various means of outputting text and symbolic information.

In addition to the above changes, the text of the standard has been supplemented with requirements for fire alarm transmission systems in terms of both facility and terminal equipment, requirements for some technical means operating as part of fire alarm automation systems, such as short-circuit isolators, remote indication devices, and devices for monitoring the operability of fire alarm loops. Note that while short-circuit isolators and remote indication devices are widely used technical means, loop operability monitoring devices are used extremely rarely.

Most often, loop performance monitoring devices are intended for installation at the end of a non-addressable fire alarm loop, and their operation is reduced to providing optical indication (most often — blinking of the optical indicator) when there is voltage in the loop. The use of these devices allows a representative of the supervisory authority to quickly verify that the loop is actually connected to the control and monitoring device and that the detectors installed in this loop are, with a certain degree of probability, activated.

For addressable loops, there is usually no need to use such a device, since most addressable detectors themselves provide blinking of their indicators in standby mode, which is regulated by the provisions of the current version of the standard.

Considering the common negative practice of unauthorized disconnection of non-addressable loops at a facility (so as not to interfere with life), it makes sense to require mandatory use of loop operability monitoring devices, but it is much more effective to transfer to mandatory status the requirement to ensure blinking in standby mode of the optical indicator not only for addressable, but also for non-addressable detectors. In this case, the need to install loop operability monitoring devices completely disappears, and a representative of the supervisory authority who comes to inspect the facility will be able to confidently state the involvement of each detector in the alarm system. The cost of such an «improvement» of non-addressable detectors is negligible, and the benefit from introducing this function is considerable. In this regard, in the new version of GOST, the requirement for blinking of optical indicators of non-addressable detectors in standby mode has been transferred from the recommended to the mandatory category.

During the discussion of the new edition of the standard, not everyone was happy about the introduction of this requirement. As a counterargument, it was stated that the current consumption of the detector at the moment of switching on the optical indicator increases significantly, and since the frequency of blinking of the detectors installed in the loop can be different, there is a possibility that all the detectors in one loop will blink at the same time, which will lead to a current surge in the loop and the device generating a false notification of a fire or malfunction.

From our point of view, this argument cannot be taken into account, since the duty cycle of the signal generated to turn on the LED (the ratio of the pulse repetition period to their duration) can reach several hundreds or even thousands. At the same time, the energy required to generate an optical pulse can be accumulated in a capacitor with a significant charge time constant, i.e. a very low charge current (units of microamperes), which will have virtually no effect on the current consumed by the detector.

Gas fire detectors are still left behind the scenes. The main reason for the lack of regulatory requirements for them is the incomplete amount of information about the technical features of these devices in terms of the possibility of their use for fire detection. The sensors used to construct gas detectors, based mainly on electrochemical cells, are usually not selective, i.e. they are capable of responding to a series of gases similar in chemical activity. This fact indicates that a gas detector designed, for example, to detect carbon monoxide, is capable of responding to a number of other underoxidized
gases, which to a certain extent limits the scope of application of such a detector.

In this regard, when forming requirements for gas detectors, it is impossible to limit ourselves to the parameters of its sensitivity to the concentration of the registered gas. It is also necessary to determine the parameters of insensitivity to other gaseous products. Such requirements are partially formed in the draft international standard for detectors that respond to carbon monoxide, however, from our point of view, it is impractical to simply translate the international standard and put it into effect as a national one due to its imperfection. In the near future, the Federal State Institution VNIIPO EMERCOM of Russia plans to carry out research work on this topic, conduct the necessary series of experiments within the framework of this work and, based on the results obtained during the work, form specific requirements for gas detectors for their subsequent introduction into the standard. The planned date for the next revision of GOST is 2014.

In conclusion, it should be noted that the appropriateness and correctness of the changes made to the standard can only be confirmed by the practice of its subsequent application. It is hoped that the new requirements will benefit the quality of fire-fighting products manufactured for the construction of fire-fighting automation systems and will become an additional barrier to protect the domestic market from non-compliant products.

_________________________________________________

V. Zdor
Deputy Head of the Research Center
of Fire-Rescue Equipment,
Head of the Fire-fighting Automation Department
FGU VNIIPO EMERCOM of Russia

Source: magazine «Algorithm of Safety» No. 5, 2011