Solutions to protect you from explosion, gas leaks and fire

SMI Sicurezza e automazione SRL offers customized explosion, gas leaks and fire protection solutions for all systems installed in mills, joinery workshops, feed mills, food and chemical industries, automotive firms where powders, vapours, mists and gases are produced, treated, packaged and stored.
The solutions we offer give an innovative service that safeguards investments by avoiding costly rebuilding and helps save considerably in terms of economy and time.
Our explosion suppression systems guarantee:




by integrating perfectly with existing industrial productive facilities without slowing or hindering operation and thus hedging any impact  on performance to minimum level.


risk assestment

SMI Sicurezza e Automazione SRL provides for every step in designing and development by offering:


The team of highly specialised SMI engineers can propose the following:


The advanced explosion prevention systems designed by SMI SRL are capable of stopping events that could generate early alarm from triggering.

Prevention by checking, analising, for example, a sample atmosphere in order to reduce oxygen standards, or by instantly intercepting sparks and smoke due to an explosion or by monitoring the concentration of toxic or inflammable gases within a certain area… is of extreme importance as to how to enact appropriate countermeasures in real time such as:

By reducing the oxygen content, the mixture of air/gas  or vapour, or air/combustible powder can be shifted out of the explosive range. Through quick and thorough analysis of the sample of the atmosphere, using safety logics, the parameters which are key to the safety of the process are kept under control.

The system used for detecting and extinguishing sparks is based on IR and UV sensors. Sparks and smoke generated by an explosion and that linger in processing are immediately intercepted so that adequate countermeasures can be enacted in real time.

Water spraying nozzles, extinction barriers and interception devices are the parts that prevent the ignition source from spreading towards other parts of the plant thus guaranteeing prevention of ignition thanks to:
▢ Reliable detection also by means of dirt deposit or high content flows.
▢ Rapid automatic extinction system consisting of a high speed electro-valve and several extinction nozzles.
▢ High pressure is extinguished in only a few seconds with a thin film of water.
▢ Maximum efficacy in dim areas.
▢ Each alarm system has three detectors and this assures highly reliable detection in high working temperature areas.
▢ Fast and easy installation also on pre-existing applications.
▢ Interface with process automation in order to provide detailed information concerning the state of the system.

Gas detection systems monitor the concentration of toxic, flammable gases, the presence of vapours or the concentration of oxygen within the area. These systems are modular, combinable and adaptable in size to the customers’ specific requirements. Further safety measures can be implemented to manage pre-alarm and alarm circumstances (actuation of forced ventilation, power supply system shut off…). By conveniently positioning the sensors and guaranteeing correct volume coverage, in some cases, ATEX classified zones can be declassed or the type and expansion can be considerably reduced.

Many industrial processes that involve stocking and handling of combustible powders and flammable liquids are characterised by operations that produce separation of electrostatic charges; if appropriate conditions of equipotentiality of the components involved are not guaranteed, the build up of charges and consequent increase of the electric field can induce breakage of the dielectric and generate ignition sources that are potentially impactful. Equipotentiality can be monitored by means of dedicated devices, fitted with visual indicators and/or signal contacts that can be used as a interlock system with the process automation.  SMI srl offers in field measuring services aimed at checking and guaranteeing correct equipotentiality of the various components of the plant where the extension of the lines (i.e. pneumatic conveyor plants and powder stockage) do not allow realistic equipotentiality monitoring by using dedicated instruments.

Sicurezza SMI Manta


Whoever is familiar with explosions and the related consequences knows that secondary explosions cause greater damage.

It is a mistake to protect only the volumes or the part of the plant that may be considered more at risk and this can allow the explosion to reach other sections of the plant and become considerably more powerful due to precompression. If this happens, an explosion protection system will not be efficient. For this reason, isolating from explosions is an essential component when developing concepts of protection against explosions.

SMI srl engineers and developers guarantee high level safety by adapting the concept of anti-explosion safety to the customer’s requirements concentrating on managing isolating systems. Depending upon the type of technology that is used, the process can be re-started immediately after activation without periods of inactivity or costs due to repairs.

Chemical barriers work following the same principle of explosion suppression systems. These barriers are activated by the sensors and controlled by the electrical panel. The main difference being that these cylinders, strategically located in the pipes, and  the suppressors of the protected equipment  are activated simultaneously therefore before the explosion occurs. The chemical barrier releases an inert agent (usually an extinguishing powder) that prevents both the flames from spreading and the effects of pressure. Such isolating system can be as efficient as an ultrarapid mechanical valve and the relevant advantages increase with larger diameter interconnection pipes. SMI srl engineers will guide you towards this technological option on the basis of your process and installations. These devices hold ATEX certifications as do all of the anti-explosion systems that we offer.


Passive valves are generally used to guarantee explosion isolation in ventilation and depowdering systems. There are two types of passive valves:
▢ Clapet: installed only in horizontal position and on ventilation inlet systems.
▢ Bulb: installed in both horizontal and vertical positions, on inlet and output ventilation systems.

The positions of Clapet and Bulb valves in controlled by position indicators which are process automation retroactions that communicate the state of the valve and guarantee all necessary emergency halts.
These valves do not require pressure or IR detectors since, as they are passive, they are activated by the pressure waves generated by the explosion.

In many cases these devices allow the benefit/costs ratio to be maximized.

FloatValve 1 169x300 2-SMI/Zanocco

The ultra-rapid knife gate valves are devices that isolate pipes carrying gas, vapours or flammable powders that are activates when an explosion is detected (by measurement of pressure or IR). SMI srl can install knife gate valves, that close in few milliseconds, that are activated by either dedicated gas generators or by a compressed air lung connected directly to  the general electric grid. These valves can be fitted with further compressed air auxiliary opening and closing systems. A sensor checks the exact position of the valve blade at any time. Last generation braking systems (compressed air brake or aluminum bearing brake) guarantee simple and swift reconditioning and refreshing following activation. The valves are available in several versions and materials, starting from the standard version through to specific applications (food or pharmaceutical processes) that require particular solutions and materials (FDA, sterilisation etc). Today many chemical, pharmaceutical, cosmetic, agri-food industries use our apparatus in their plants.


Venting devices make anti-explosion protection of volumes and process apparatus possible by controlling the discharge of explosions. These devices are made of set fragmentation metal surfaces (rectangular or round, flat or convex or, in some cases, customized) that, once the explosion is ignited inside a volume, open allowing discharge before internal pressure causes damage or breakage in areas that are not controlled by the system. The size of the devices can follow various standards (EN14491, EN14994, NFPA 68 etc) based on the shape of the volume that needs protecting, on the structural resistance and the characteristics of the potentially explosive compound. Venting devices are equipped with a breakage indicator that is used for retro-activating the state of the device to the process automation and implement any necessary emergency halts.


Using venting devices implies the possibility of discharging the effects of an explosion (flame front, pressure wave) to a safe zone where no damage can occur to people or structures. When this situation is not guaranteed indoor venting devices can be applied that is venting devices fitted with a flame arrestor. These devices, when of adequate capacity, allow explosion venting methods to be applied also to indoor situations or in those where a large enough safe area is not available in the proximity of the equipment that needs protecting.



SMI srl proposes, for industrial processes, various types of venting devices that  discharge and divert the effects of an explosion to a safe area, far from people and objects (venting devices) or that can contain such effects in safety also in indoor applications or restricted areas (indoor venting devices).


Explosion suppression systems are becoming more and more important and widespread because of their reliability and because they can guarantee swift reactivation of the plants and machinery they protect even following an explosion. Explosion suppression systems trigger within milliseconds; thanks to optical or dynamic pressure detectors, the explosion is immediately located and quenched by activating extra-rapid extinguishing systems. Handling and extinguishing the deflagration in the initial stage enables efficient damping of the effects of over-pressure and temperature, safeguarding not only people but limiting structural stress on protected apparatus to minimum levels in order to maintain the integrity of the productive plant.

The protection system control unit, which is designed to guarantee SIL 2 level reliability, continuously monitors the components of the protection system for reliability and functionality.

Developing new extinguishing agents (FDA powders, hot water technology extinguishing systems) and nozzles for CIP and SIP cycles, allows these systems to be applied in locations with extremely high hygiene requirements such as in pharmaceutical and food industry.

The suppressor is activated when an explosion is detected by two generator gases; a dedicated valve fixed to the head, which can easily be replaced after the event, guarantees fast opening and discharge of the extinguishing agent. Nitrogen is the vector. Rapid inlet of the extinguishing powder and nitrogen dampens the combustion in its initial stage before over-pressure and thermal effects can reach relevant levels.
Following activation, the valve can be quickly replaced and the suppressor recharged thus reducing plant downtime.
All functions of the suppressor (pressure level, activation system, position of lock pin) are constantly monitored by the protection system control unit to ensure real time diagnosis.

The suppressors can guarantee:
▢ Safety during operation and maintenance thanks to mechanic lock pin.
▢ Reliable activation system due to redundant generator gases.
▢ Fast reactivation due to replacement of activation valve.
▢ Low cost extinguishing agent.
▢ Easy replacement (Plug in connector).


The dynamic pressure sensor can detect an increase of pressure linked to an explosion. The reliability of the sensor is based on consolidated automotive technology. The mechanical characteristics of this sensor make it suitable for use where strength is a key requirement but also where there are extremely high hygiene and sensitivity requirements and can be optimally positioned according to the volume that needs to be monitored.

The sensors check the pressure trend non-stop, sending this information to the control unit; when an alarm is detected, the pressure curves are saved in the internal memory of the sensor for diagnosis and analysis of the events.

In order to increase reliability and actuation rapidity of the protection systems on some particular configurations, dynamic pressure sensors can be combined with infra-red optical sensors.


The control unit is the core of the protection system; by receiving information from the dynamic/optical pressure sensors and based on set levels, it gives the suppressor activating signal.

Calculation for defining the activation signal is bound to the front of pressure increase that defines the time limit within which the explosion must be suppressed: as a general rule, the greater the volume that needs protecting, the greater the time for effectively suppressing the explosion.

The control unit guarantees continual monitoring of the reliability of all components of the protection system; the unit is modular and can be customized and thus aimed interfacing between the protection system and the process automation is a fact due to customized emergency stops and securing the process.

Impianti di automazione industriale

In order to ensure effective release of the extinguishing agent in many types of machinery and processes, several types of nozzles have accordingly been developed:  the use of stainless steel combined with careful design allows them to be installed and employed in high hygiene standard processes.

Flexible connectors enable the extinguishing agent to be inlet to operating machinery such as fluidized beds or sifters.

Ugelli Cuneo SMI Zanocco


Designing and installing fire prevention systems

Fire detection systems must safeguard people, assets and premises within the protected areas, promptly reporting the occurrence of dangerous situations.

Evaluation of the type of fire hazards in the locations that need protection is the starting point for choosing the most suitable system. SMI srl protection systems and solutions are developed by fire protection and anti-explosion experts who have wide experience in this sector and in safety technologies.

Impianti SMI Zanocco antincendio

SMI SRL provides fire protection solutions such as:

There are four main systems proposed:

A fire prevention system to be used in two new tunnels has been developed. This system is unique because pointing of the monitors is completely automated. The monitors are nothing more than fire-fighting lances driven by three electric motors controlled by a PLC unit. The fire protection system receives a position signal, which is discretized every 10 meters inside the tunnel and provides an indication of where the monitors are to be pointed. Following this the control software proceeds with the mathematical calculations required for positioning the monitor in order to allow the jet to reach the fire point. Zanocco has developed and built 120 “slave” electrical panels for the management of individual monitors and 2 “master” electrical panels to house all the control systems of the plant. SMI srl has developed all the automatic tracking software of the monitors and is one of the first companies in the world to have devised a pointing system and an automatic fire extinction system for tunnels. 

Here follows a video showing the first test carried out on open air extinction.

Sistema di estinzione incendio gallerie

The hermetically sealed system is composed by a pipe sensor fitted in the area to be monitored and has a hermetic cap on one end. At the other end the pipe sensor is connected to the detector box, more specifically to a fully electronic pressure sensor and to a pneumatic control device. The entire pneumatic system contains normal air. The control mechanism consists of a geared motor and a pump. The pressure sensor continuously measures the absolute pressure inside the tube sensor. The sensor signals are analysed mathematically by the microprocessor and can therefore be used to calculate and to realize the differential behaviour. If the pressure increases at the speed defined by the software (mbar / s), the ADW signals a differential alarm. Disturbances (temperature fluctuations due to weather) are filtered. The absolute maximal behaviour of the ADW is designed so that the pressure corresponding to a maximum temperature triggers the alarm, the slow growth and constant pressure over a long period, which is sufficient to trigger the differential function, is then seen as an alarm limit.

The ADW will be installed in a Safe area, while the sensor tube (galvanically insulated) can be placed in the ATEX21 ZONE. A firefighting main unit will be installed (SFP) for the ADW alarm management and correct reporting of an alarm, malfunction or failure.


The ASD System consists of one or two independent pipes with the related suction holes and one or two high sensitivity smoke detectors. By means of a dedicated device the two air flows are constantly monitored to detect any breakage of the pipes or clogging of the holes. A powerful fan draws air from the room or from the equipment to be monitored and conveys it through the pipe to the terminal processor. Here the smoke sensors constantly analyse the air. The control and signaling processor indicates the concentration of smoke in the air intake and the other messages of alarm, failure and status. An increase in the concentration of smoke is quickly detected. 
It is possible to program three pre-signals and a main alarm, transmitted via potential-free relay or directly on the loop line. There are four other free slots to allow additional relay modules, interfaces or memory cards to be installed.

Thanks to its excellent response performance, the ASD system is ideal for monitoring equipment and premises. ONE ASD535 DETECTOR (two SSD535 sensors) MONITORS TWO 1200 SQUARE METERS AREAS AND THEREFORE A TOTAL AREA OF 2400mq !!!


The fire detection system for your safety has a highly developed intelligence and reliability and outshines all the systems known so far. It offers extraordinary innovation: it is totally redundant and is designed to ensure double safety which excludes almost any system failures.

All hardware and software components are available in the redundant version and work in parallel as two separate and independent systems If the active system fails, the secondary system takes over the operational process without interruption. This ensures maximum safety and immediate detection of any event of fire, even if the system is damaged by the interruption of several wires.

Modular, decentered structure allows maximum designing freedom. Up to 16 autonomous main control units can be combined in one integral, homogeneous system without the use of a master computer. To each of these interconnected stations up to 14 loop lines with 128 elements each can be connected such as fire detectors and manual call points. While the main unit is fulfilling its main task, which is immediate recognition of fires, the system communicates outwards on several levels. It is connected via interfaces to transmission and alarm equipment, relay outputs as well as monitored inputs and outputs. The planimetric panels and command panels for the firemen are connected via bus to an external unit while contact with higher-level systems is ensured by serial data interfaces. The innovative system can be designed, programmed and controlled in a simple and intuitive way.



SMI Sicurezza e Automazione SRL is one of the few companies worldwide that can guarantee maintenance of explosion prevention systems in Italy and abroad. We offer:

Phone +39 0175 289730


Via Unità d’Italia n. 19, 12030
Manta (CN), Italia

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Telefono +39 0175 289730


PARTITA IVA e C.F. 03162330041 | Reg. Imprese Cuneo CN199739418 | Capitale Sociale i.v. € 100.000,00

Copyright © 2021 SMI Sicurezza e Automazione SRL Tutti i diritti riservati.

Telefono +39 0175 289730


PARTITA IVA e C.F. 03162330041 | Reg. Imprese Cuneo CN199739418 | Capitale Sociale i.v. € 100.000,00

Copyright © 2021 SMI Sicurezza e Automazione s.r.l. Tutti i diritti riservati.