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FM 558977

BSI ISO 9001:2008 Certficate





  Information Zone



Selection & Application

Audible & Visual Warning Signals

The environment in which the warning signal is to be installed will determine the product selection.


A signal designed for heavy industrial applications, incorporating a high decibel (dB) rating & high light intensity (20J) would not be suitable for local signalling at a control panel. Alternatively a low dB & light intensity (2J) would be ineffective for a large factory environment. Moflash can supply warning signals to

cover all applications. Listed below are some of the main market areas.


Moflash Beacon Group

Industrial & Marine

Warning beacons for heavy duty, high light output applications such as foundries, factory shop floors, large warehouses, docks, ports and general offshore use etc. For further information see our Industrial & Marine section.



Warning beacons for use on automobiles (commercial & private) agricultural / off road vehicles and forklift trucks etc. For further information see our Automotive section.



Warning signals designed & complying with the latest European standards for use in all commercial buildings used as fire evacuation signals. For further information see our Acoustic Section


Obstacle Marking for Aerodromes

Visual warning signals that comply with the International Civil Aviation Authority (ICAO) requirement for the marking of objects in and around Aerodromes. For further information see our Obstacle Marking section.


Explosion Proof

Warning signals designed for use in potentially explosive atmospheres and complying with the latest global standards. Typically used on oil rigs, refineries, chemical plants, grain storage etc. where in normal operations the atmosphere is flammable/ignitable etc. For further information see our EXD Explosion Proof section.


Environmental Factors Determining Selection

•   Safe atmosphere or potentially explosive atmosphere;

•   The ambient level of noise and / or existing light;

•   The ambient temperature

•   The duration the beacon has to operate for

•   The Ingress protection (IP)  required of the signal enclosure

•   The electrical supply available.

Installation and Maintenance of Visual Warning Beacons

When installing a Hazard Warning Beacon, care should be taken to position it in the most effective location to allow for all round light visibility and to maintain the IP (Ingress Protection) rating of the beacon. Therefore the following parameters should be noted:

  • To maintain the IP rating, the beacon should be mounted with the dome above the black molded base. Never mount the unit with the dome horizontal or below base position.
  • Always fit mounting gasket provided (200/1, 400/1 & 500/1 series models only) and ensure the ‘O’    ring is in place between the dome and base.
  • Fit a suitably IP rated cable gland (not supplied) where appropriate.
  • Regularly clean the beacon dome, as this will improve light output and help dissipate heat build-up in the beacon.  Do not clean dome with petroleum based cleaners.
  • Areas of vibration should be avoided.  If this is not possible, then our Anti-Vibration mount must be   used. Reference 50080 (available for 88/125 & 200/1 series models only).
  • Avoid situation Xenon beacons in close proximity to communication aerials or equipment and power lines that may be subject to high voltage transients.
  • DC voltage Xenon beacons should only be run on a smoothed rectified supply.
  • Unlike Incandescent lamps which fail instantly, Xenon tubes deteriorate very slowly. The impending failure of the tube will be indicated by erratic flashing. Once this is recognised the tubes should be replaced immediately.  Failure to do so may result in damage to the electrical circuit.
  • Always disconnect the beacon from the supply before attempting maintenance.  In addition, allow Xenon beacons at least 15 minutes to self-discharge before removing the dome as high voltages will remain on the pcb for this period of time.



Types of Warning Signals - Audible



Airhorns are non-electrical devices that only operate from a compressed air supply. They offer very high dB output with very low frequency sound making them ideal for very noisy environments. Moflash offers an industrial and marine range. Being non-electrical they can be used in hazardous area Category 1 use.



Bells are a cost effective traditional signalling device with a wide range of signalling applications. They offer medium dB output with a unique sound. Moflash offers two types: solenoid driven for industrial applications where they are under constant daily use, and a motor driven type more suitable for fire alarm applications.


dB Chart

Click to download Moflash’s dB (A) Chart

Note: This chart displays the theoretical attenuation in perfect conditions in an open area without obstruction. In addition, the sound frequency of the signal used will have a marked effect on the decibel reading at any given point. A much lower sound frequency will achieve a higher dB rating over longer distances (say +3dB against this table) than a much higher sound frequency (say -3dB).





Either Electro Mechanical type where the diaphragm is deflected by a moving magnet which is triggered by a make and break contact of the Piezo type where the diaphragm is controlled by an electronic circuit.  The Mechanical versions offer medium/high dB output with low frequency sound and are of robust construction.


Piezo versions are relatively low dB and high frequency and are only suitable for local signalling applications.


Electronic Sounders

The Electronic Sounders are now the most versatile audible warning devices on the market today.


With multiple tone & decibel selections these type of products will satisfy most applications with the added benefit of remote tone selection & voice activation.



Hooters are powerful motor driven horns producing the unique and never forgotten ‘Klaxon’ sound used the world over. A serrated rotor driven against a hardened steel diaphragm stud creates a high dB output with low frequency sound. These types of signals are ideal for indoor and outdoor applications where a rugged and durable sounder is required.



Sirens are powerful motor driven signals driving an internal impeller through a slotted cover creating a unique penetrating sound, traditionally recognisable for creating the ‘air raid’ warning signal.




Types of Warning Signals - Visual


Rotating Beacons

A parabolic reflector, driven by an electric motor, revolves around a continuously illuminated bulb on the vertical axis of the beacon creating a powerful beam of light travelling through 360 degrees.


These units are available with either a filament or a tungsten halogen bulb. In general, this type of beacon has a greater degree of light output than other models but this is reduced as the parabolic reflector only illuminates one given point at a time.


Flashing Filament

Operating through an internal circuit, which simply cycles the bulb On, and Off. These types of beacons generally give a much lower light output as it takes longer for the bulb to fully illuminate itself.


The effective brightness can be increased by use of a Diotropic (Fresnel) lens which is placed over the internal cap, capturing the light emitted, magnifying and directing it to create a more effective warning signal. In terms of light coverage this type of beacon is more efficient as it illuminates the total surface constantly through 360 degrees.


Static Filament (Continuous) Beacons

These units are identical to Flashing Filament beacons with the exception that they do not operate through an On, and Off cycle. When the unit is energised the light source stays permanently ‘On’.  


The main advantage of this type of beacon is that the light can be controlled by a separate source i.e.. a control panel, giving the unit more flexibility.







Xenon (Strobe) Beacons

A discharge capacitor operating through a converter circuit ignites xenon gas inside a tube creating a brilliant flash of light. Xenon gas ignites virtually instantaneously so maximum brightness is obtained immediately. This signal can be improved further by the use of a Dioptric (Fresnel) lens as described earlier. In some Moflash models a ‘Double Flash’ option is also available this extends the signal duration making it more noticeable to the human eye. See X88, X201/200, X401/400 X501/500.


Xenons have an added advantage of low current consumption combined with long life. The tube life of a xenon beacon is approximately 5 million flashes. These units are the most efficient available incorporating a 360 degree light output with the brightest and most effective visual signal.


LED Beacons

A light emitting diode (LED) is a semiconductor device that emits visible light when an electrical current passes through it. The four major benefits of LED technology incorporated into warning beacons are:


•   Low power requirement

•   High efficiency

•   Very Long Life

•   Multiple colour signal options in a single

     beacon enclosure.


Moflash offer a range of LED options, from beacons containing 8 off LEDs up to 144 off LEDs in a single enclosure. They can be set in various modes of operation from Flashing, Static and Rotating. Some beacons have a combined Audible & Visual option. Ethernet compatible and PLC controllable beacons also make up the range along with high ‘Ingress Protection’ enclosures.


Levels of Brightness

Brightness depends upon the type of beacon chosen, the rated power output of the unit i.e. Watts and Joules, the distance that the signal is observed from and the dome colour of the beacon used.  In general, if the viewing distance is doubled, the light intensity observed is reduced to a quarter and if the distance is quadrupled the light intensity is reduced to a sixteenth.


Beacon Lens Colours

The intensity of the light can be greatly reduced as it passes through the dome of the beacon.  The extent of this reduction is dependent upon:


  • The type of light source used i.e. conventional filament (Incandescent) bulb, tungsten halogen bulb or a xenon tube.

  • The colour of the beacon lens that is used.

Lens colours available are shown in the below table:

Beacon Colour Types


The next table gives an indication of the percentage of light that will pass through the beacon dome for different light sources and dome colours.

Percentage of light that will pass through a given beacon dome colour type


Dome colours convey different messages to the observer:

Beacon Colour Messages


Alternatively, green beacons are used by Doctors and Veterinarians and blue beacons for the Police and Fire departments.



IP Ratings

The IP ‘Ingress Protection’ rating system provides a means of classifying the Degrees of protection from dust and water afforded by electrical equipment and enclosures.  The system is recognised in most countries and is set out in BS EN60529 1992 Degrees of Protection.


Click to download our IP Ratings Chart



Approvals & Conformities

The CE Mark

The Moflash products that show the CE mark, are deemed to comply, where applicable, with the EMC Directive No: 89/366/EEC and additional amendments, regarding Electromagnetic Compatibility which states that:


‘An electrical product must not be susceptible to, or generate certain levels of, electromagnetic  

Interference liable to interfere with other

electronic equipment.’


and the LVD Directive No: 2006/95/EC regarding low voltage electrical material which states that:


‘Electrical equipment within the voltage ranges of

50 to 1000v Ac and 75 to 1500v Dc are  constructed within the principles of good engineering practice

and provide adequate levels of  protection against

an electric shock’.





  CE Mark     Tick







  • Convention on International Civil Aviation ICAO Doc 7300/5
  • Annex 14-Aerodromes, Chapter 6, Table 6-3 (Appendix A)
  • Characteristics of obstacle lights, Low-intensity, Type A, red
  • General administrative regulation on the marking of aviation obstructions of 02.09.2004.



Sets out the standards required at UK Licensed aerodromes relating to physical characteristics, assessment and treatment of obstacles, visual aids, rescue and fire fighting.


More information



The Machinery Directive 2006/42/EC

These directives are designed to harmonise wide range health and safety requirements in machinery design and daily use by indicating a potential hazard by the use of an immediately recognizable audible or visual warning signal.


prEN 842 Safety of Machinery

Visual Warning Signals

Classifies the type of warning light and specifies the characteristics the warning light must achieve to conform to the machine directive.


Warning Signals

Visual warning signals must be at least five times brighter than the area where they are used.


Danger Signals

Clearly visible even in strong light, distinguishable from other lights and Visual warning signals and be understood immediately.


Emergency Signals

These have the highest priority and must be at least ten times brighter than the area that they are to be used in and understood immediately


IEC 60073 - Colours of Luminous Indicators & Push Buttons

Establishes the various meanings of coloured luminous indicators and push buttons to conform to the machine directive.


Colour: RED


  • Danger of live or unguarded
  • Moving machinery or essential

    Equipment in protected zone


Colour: AMBER


  • Temperature of pressure different from normal level


Colour: GREEN


  • Checks complete the machine is about to start


Colour: BLUE


  • Pre-set ready or remote control


Colour: CLEAR


  • Could confirm an earlier message


All Moflash coloured domes are manufactured from ‘UV’ stable polycarbonate plastic that will not tarnish, fade or become brittle over a period of time unlike many domes available that are produced from  Acrylic plastic.



RoHS (Restriction of Hazardous Substances)

The RoHS Directive 2002/95/FC comes into force on 1st July 2006 and restricts the use of certain hazardous substances in electronic and electrical equipment within the European market. Although it is also widely referred to as the 'Lead Free Directive', but you should also take note that the following substances listed below are also restricted:



Hazardous Substance

Allowed PPM Level

Cadmium (Cd) 100ppm (0.01%)
Lead (Pb) 1000ppm (0.01%)
Mercury (Hg) 1000ppm (0.01%)
Hexavalent Chromium (CrVI) 1000ppm (0.01%)
Polybrominated Biphenyls (PBB's) 1000ppm (0.01%)
Polybrominated Diphenyl Eithers (PBDE's) 1000ppm (0.01%)


From 1st July 2006 any new electronic or electrical equipment sold in the EC must not contain these hazardous substances in excess of the permitted levels indicated above. However, the directive does allow provision for some specific exclusives such as lead in glass and ceramics etc. Equipment used for military and medical purposes, together with monitoring and control instrumentation, are also exempt.


Following the introduction of the RoHS Directive and the forthcoming restriction of lead in soldering materials different process parameter will be required to handle the new generation of solder alloys and board finishes. To assists those performing assembly, rework and repair operations the characteristics of RoHS compliant products have been categorised by JEDEC standards under three headings MSL (Moisture Sensitivity Level), PBT (Peak Body Temperature) and 2nd Level, Interconnect (Terminal Finish/Material).


Moflash conforms to the RoHs Directive.

Moflash products conform to the following WEEE Directive

The WEEE (Waste Electrical & Electronic Equipment) Directive aims to encourage a sustainable approach to the manufacture and disposal of classified electronic and electrical products and places certain obligations on producers of these products. The principle behind the legislation is simply to remove some of the responsibilities for disposal costs from the end user to the producer, to facilities improvements in environment performance.


WEEE applies to electrical and electronic equipment that is dependant on electric or electromagnetic fields and designed for use with a voltage rating not exceeding 1000 volts for alternating current and 1500 volts for direct current, for equipment falling into the following categories:

  • Large household appliances
  • Small household appliances
  • IT and telecommunications equipment
  • Consumer equipment
  • Light equipment
  • Electrical and electronic tools
  • Toys, leisure and sports equipment
  • Medical devices
  • Monitoring and control equipment
  • Automatic

WEEE Directive Symbol




Environments with Potentially Explosive Atmospheres


Moflash offers a range of Audible & Visual warning signals along with manual activation devices that have been designed for use in harsh environmental conditions and potentially explosive atmospheres or as sometimes known, Hazardous Areas or Hazardous Locations.


All of these products comply with European ATEX directive 94/9/EC (to be superseded by 2014/34/EU with April 2016) and the International Electrical Commission (IEC) for Explosion atmospheres IECEx.


Moflash ATEX & IECEx certificates have been issued by DNV NEMKO Norway.


These directives help classify areas where hazardous explosive atmospheres may occur into zones. The classification given to a particular zone, and its size and location, depends upon the likelihood of an explosive atmosphere occurring and its persistence if it does. Areas that have been classified into zones must be protected from effective sources of ignition. The equipment & protective systems intended to be used in zoned areas must meet the requirements of the ATEX directive.


Zone Classification

European and IEC Classification

Definition of Zone or Division

North American Classification

Zone 0


An area in which an explosive mixture is continuously present or present for long periods.

Class I

Division 1 (gases)

Zone 1


An area in which an explosive mixture is likely to occur in normal operation.

Class I

Division 1 (gases)

Zone 2


An area in which an explosive mixture is not likely to occur in normal operation and if it occurs it will exist only for a short time.

Class I

Division 2 (gases)

Zone 20


An area in which an explosive mixture is continuously present or present for long periods.

Class II

Division 1 (dusts)

Zone 21


An area in which an explosive mixture is likely to occur in normal operation.

Class II

Division 1 (dusts)

Zone 22


An area in which an explosive mixture is not likely to occur in normal operation and if it occurs it will exist only for a short time.

Class II

Division 2 (dusts)


Gas Groups

Explosive gases, vapours and dusts have different chemical properties that affect the likelihood and severity of an explosion. Such properties include flame temperature, minimum ignition energy, upper and lower explosive limits, and molecular weight. Empirical testing is done to determine parameters such as the maximum experimental safe gap, minimum ignition current, explosion pressure and time to peak pressure, spontaneous ignition temperature and the maximum rate of pressure rise. Every substance has a differing combination of properties but it is found that they can be ranked into similar ranges, simplifying the selection of equipment for hazardous areas.


Flammability of combustible liquids are defined by their flash-point. The flash-point is the temperature at which the material will generate sufficient quantity of vapour to form an ignitable mixture. The flash-point determines if an area needs to be classified. A material may have a relatively low auto-ignition temperature yet if its flash-point is above the ambient temperature, then the area may not need to be classified. Conversely if the same material is heated and handled above its flash-point, the area must be classified.


Each chemical gas or vapour used in industry is classified into a gas group.



Representative Gases




All Underground Coal Mining, Firedamp (methane)


Industrial methane, propane, petrol and the majority of industrial


Ethylene, coke oven gas and other industrial gases


Hydrogen, acetylene, carbon disulphide


Group IIC is the most severe group. Hazards in this group can be ignited very easily indeed. Equipment marked as suitable for Group IIC is also suitable for IIB and IIA. Equipment marked as suitable for IIB is also suitable for IIA but NOT for IIC. If equipment is marked for example, Ex d IIC then it is suitable for all subgroups



A list must be drawn up of every chemical gas or vapour that is on the refinery/chemical complex and included in the site plan of the classified areas. The above groups also indicate how much energy is required to ignite the gas by spark ignition, Group IIA requiring the most energy and IIC the least.




Effective Ignition Sources

Is a term defined in the ATEX directive as an event which, in combination with sufficient oxygen and fuel in gas, mist, vapour or dust form, can cause an explosion. Effective sources of ignition are:

  • Lightning strikes
  • Open
  • Flames
  • Mechanically generated impact or friction sparks
  • Electric sparks
  • Very high surface temperatures
  • Electrostatic discharge & adiabatic compression etc.



Equipment Protection Level

In recent years the Equipment Protection Level (EPL) is specified for several kinds of protection. The required protection level is linked to the intended use in the zones described below:


Ex Risk



Minimum type

I (mines)





I (mines)

de-energised in presence of Ex atmosphere




II (gas)

explosive atmosphere > 1000 hrs/yr



ia, ma

II (gas)

explosive atmosphere between 10 and 1000 hrs/yr



ib, mb, px, py, e, o, q, s

II (gas)

explosive atmosphere between 1 and 10 hrs/yr



n, ic, pz

III (dust)

explosive surface > 1000 hrs/yr




III (dust)

explosive surface between 10 and 1000 hrs/yr




III (dust)

explosive surface between 1 and 10 hrs/yr






Temperature Classification

Another important consideration is the classification

of the electrical equipment. The surface temperature

or any parts of the electrical equipment that may be exposed to the hazardous atmosphere should be tested that it does not exceed 80% of the auto-ignition temperature of the specific gas or vapour in the area where the equipment is intended to be used.


The temperature classification on the electrical equipment label will

be one of the following (in degrees Celsius)




(IEC) °C

Germany °C Continuous - Short Time




G1: 360-400




G2: 240-270




G3: 160-180




G4: 110-125




G5: 80-90









The above table tells us that the surface temperature of a piece of electrical equipment with a temperature classification of T3 will not rise above 200°C.




Auto-ignition Temperatures


The auto-ignition temperature of a liquid, gas or

vapour is the temperature at which the substance

will ignite without any external heat source. The

exact temperature value determined depends on

the laboratory test conditions and apparatus. Such temperatures for common substances are:-
















Carbon Disulfide


The surface of a high pressure steam pipe may be above the auto-ignition temperature of some fuel/air mixtures auto-ignition temperatures.


Auto-ignition Temperatures (dust)

The auto-ignition temperature of a dust is usually higher than that of vapours & gases. Examples for common materials are:










Grain Dust






Type of Protection

To ensure safety in a given situation, equipment is placed into protection level categories according to manufacture method and suitability for different situations. Category 1 is the highest safety level and Category 3 the lowest. Although there are many types of protection, a few are detailed below:


Ex Code







Equipment construction is such that it can withstand an internal explosion and provide relief of the external pressure via flamegap(s) such as the labyrinth created by threaded fittings or machined flanges. The escaping (hot) gases must sufficiently cool down along the escape path that by the time they reach the outside of the enclosure not to be a source of ignition of the outside, potentially ignitable surroundings.

Equipment has flameproof gaps (max 0.006" (150 um)propane/ethylene, 0.004" (100 um)acetylene/hydrogen).

IEC/EN 60079-1

Zone 1 if gas group & temp, class correct

Motors, lighting, junction boxes, electronics

Increased Safety


Equipment is very robust and components are made to a high quality.

IEC/EN 60079-7

Zone 2 or Zone 1

Motors, lighting, junction boxes

Oil Filled


Equipment components are completely submerged in oil.

IEC/EN 60079-6

Zone 2 or Zone 1


Sand/Powder/ Quartz Filled


Equipment components are completely covered with a layer of sand, powder or quartz.

IEC/EN 60079-5

Zone 2 or Zone 1

Electronics, telephones, chokes



Equipment components of the equipment are usually encased in a resin type material.

IEC/EN 60079-18

Zone 1 (Ex mb) or Zone 0 (Ex ma)

Electronics (no heat)

Pressurised/ Purged


Equipment is pressurised to a positive pressure relative to the surrounding atmosphere with air or an inert gas, thus the surrounding ignitable atmosphere cannot come in contact with energised parts of the apparatus. The overpressure is monitored maintained and controlled.

IEC/EN 60079-2

Zone 1 (px or py), or Zone 2 (pz)

Analysers, motors, control boxes, computers

Intrinsically Safe


Any arcs or sparks in this equipment has insufficient energy (heat) to ignite a vapour.

Equipment can be installed in ANY housing provided to IP54. A ‘Zener Barrier’ or ‘opto isol’ or ‘galvanic’ unit may be used to assist with certification.

A special standard for instrumentation is IEC/EN 60079-27, describing requirements for Fieldbus Intrinsically Safe Concept (FISCO) (zone 0, 1 or 2).

IEC/EN 60079-25

IEC/EN 60079-11

IEC/EN 60079-27

'ia': Zone 0 & 'ib': Zone 1 'ic': Zone 2

Instrumentation, measurement, control

Non Incendive


Equipment is non-incendive or non-sparking.

A special standard for instrumentation is IEC/EN 60079-27, describing requirements for Fieldbus Intrinsically Safe Concept (FISCO) (zone 2)

IEC/EN 60079-15

IEC/EN 60079-27

Zone 2

Motors, lighting, junction boxes, electronic equipment

Special Protection


This method, being by definition special, has no specific rules. In effect it is any method which can be shown to have the required degree of safety in use. Much early equipment having Ex s protection was designed with encapsulation and this has now been incorporated into IEC 60079-18 [Ex m]. Ex s is a coding referenced in IEC 60079-0. The use of EPL and ATEX Category directly is an alternative for ‘s’ marking. The IEC standard EN 60079-33 is made public and is expected to become effective soon, so that the normal Ex certification will also be possible for Ex s.

IEC/EN 60079-33

Zone depending upon

As its certification states

The types of protection are subdivided into several sub classes, linked to EPL: ma and mb, px, py and pz, ia, ib and ic. The a subdivisions have the most stringent safety requirements, taking into account more than one independent component faults simultaneously.



Multiple Protection

Many items of EEx rated equipment will employ more than one method of protection in different components of apparatus. These would be then labelled with each of the individual methods. For example a socket outlet labelled EEx ‘de’ might have a case made to EEx ‘e’ and switches that are made to EEx ‘d’.


Table of Icons

Our Icon Legend chart is a guide explaining the various symbols seen our on our datasheets and in our catalogue for example: FPM, IP, Marine etc.


Click to download our ICON Legend Chart








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