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Hazardous Area

Fire Classification

In order to restrict the spread of fire the bulkheads and decks of a vessel are constructed to a particular standard. Various standards apply depending on the type of vessel and the nature of the space surrounded. Generally the fire resistance of a bulkhead is expressed as A, B or C followed by a number indicating the time that division will prevent a specified temperature rise.

Class "B"
A division capable of preventing the passage of flame the first half an hour of the standard test. The insulation should be such that on the side opposite to a fire the average temperature will not rise more 139 °C above the original temperature nor more than 225 °C at any one point.

Class "B-15" must prevent the stated temperature rises for at least 15 minutes.

Class "B-0" must prevent the stated temperature rises for at least 0 minutes.
A Class "B" division must be constructed of approved non combustible materials except that combustible materials may be permitted provided they meet certain other requirements.

The lighting as a separate unit cannot be fire approved. It is the complete installation with the covering of the installed unit that have to withstand the fire load.
When completing the installation you have to have in mind:

• Fire rating for ceiling installation
• The maximum allowed size of recess in the actual ceiling
• Maximum weight of fixtures/units
• Minimum allowed distance between recesses
• Recess construction
• Method of fixing
• Type of panels the lighting fixture will be accepted onto: Width and length of panel, Thickness of panel, thickness of steel plate, etc.

The installation on a vessel or a rig will never be exactly as the laboratory test installation. In practice there will be a mixing of cut out for lighting and ventilation as well as ceiling hatches. It is therefore very important to have in mind the minimum allowed distance between recess for the actual ceiling, as well as the maximum allowed load for each ceiling element.

Fire and Explosion Factors

An Explosion can only be taken place, when three factors are present simultaneously

Explosion Limits (LEL, UEL)

Below Lower Explosive Limit : Not enough fuel to ignite
Above Upper Explosive Limit : Not enough oxygen
Between LEL and UEL : Explosive atmosphere

Equipment Grouping

Group I  Used in mines susceptible to firedamp.
Group II  Used in the explosive gas atmosphere.
Group III  Used in the explosive dust atmosphere.

IIC can be used in IIB and IIA area.
IIB can be used in IIA area.
IIIC can be used in IIIB and IIIA area.
IIIB can be used in IIIA area.

*MESG : Maximum Experimental safe gap
MIC : Minimum Ignition Current Ratio (according to IEC 60079-20-1)
Ignition Energy according to IEC 60079-11. 10.1.5.3

Temperature Class for Group II (Gas or Dust)

Temperature Class for Group II

Temperature class	Max. surface temperature [°C]	Safety margin [K]
T1	450	10
T2	300	10
T3	200	5
T4	135	5
T5	100	5
T6	85	5

Types of Protection

 

Types of Protection

IEC	Latest Version	Basic Principle	Model(DAEYANG)	Division	ZONE	EPL
60079-0	Ed. 6 (2011)	General requirements This part of IEC 60079 specifies the general requirements for construction, testing and marking of electrical equipment and Ex Components intended for use in explosive atmospheres.
60079-1	Ed. 7 (2014)	Flameproof enclosures “d” Parts which can ignite a potentially explosive atmosphere are surrounded by an enclosure which withstands the pressure of an explosive mixture exploding inside the enclosure and prevents the transmission of the explosion to the atmosphere surrounding the enclosure.	PF-**SBX2	Ex da	0	Ga
				Ex db	1	Gb
				Ex dc	2	Gc
60079-2	Ed. 6 (2014)	Pressurized enclosures “p” The formation of a potentially explosive atmosphere inside an enclosure is prevented by maintaining a positive internal pressure of protective gas in relation to the surrounding atmosphere and, where necessary, by supplying the inside of the enclosure with a constant flow of protective gas which dilutes any combustible mixtures.	MPS	Ex pxb	1/21	Gb/Db
				Ex pyb	1/21	Gb/Db
				Ex pzc	2/22	Gc/Dc
60079-7	Ed. 5 (2015)	Increased safety “e” Here additional measures are applied to increase the level of safety, thus preventing the possibility of inadmissibly high temperatures and the occurrence of sparks or electric arcs within the enclosure or on exposed parts of electrical equipment, where such ignition sources would not occur in normal service.	EXLED-***ed	Ex eb	1	Gb
				Ex ec	2	Gc
60079-11	Ed. 6 (2011)	Intrinsic safety “i” Equipment that is used in a potentially explosive area only contains intrinsically safe electric circuits. An electric circuit is intrinsically safe if any spark or thermal effect produced under specified test conditions (which include normal operation and specified fault conditions) is not capable of causing ignition of a given explosive atmosphere.	-	Ex ia	0/20	Ga/Da
				Ex ib	1/21	Gb/Db
				Ex ic	2/22	Gc/Dc
60079-15	Ed. 4 (2010)	Type of protection “n” Electrical equipment cannot ignite an explosive atmosphere surrounding it (during normal operation and under defined abnormal operating conditions).	EXLED-***ed	Ex nA	2	Gc
				Ex nR	2	Gc
				Ex nC	2	Gc
60079-18	Ed. 4 (2014)	Encapsulation “m” Parts that are capable of igniting an explosive atmosphere are enclosed in a compound in such a way that ignition of an explosive atmosphere is prevented.	EXLED-EMS**	Ex ma	0/20	Ga/Da
				Ex mb	1/21	Gb/Db
				Ex mc	2/22	Gc/Dc

*EPL Ga can be used in EPL Ga, Gb & Gc ; EPL Gb can be used in EPL Gb & Gc ; EPL Gc can only be used in EPL Gc.
EPL Da can be used in EPL Da, Db & Dc ; EPL Db can be used in EPL Db & Dc ; EPL Dc can only be used in EPL Dc.
*IEC : International Electrotechnical Commission
EPL : Equipment Protection Levels

  

Zone & EPL (Equipment Protection Level)

Temperature Class for Group II

	Zone	IEC EPL	Definition
Gas	Zone 0	Ga	A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapor or mist is very likely to occur in normal operation. (>1000 h/y)
	Zone 1	Gb	A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapor or mist is likely to occur in normal operation. (10~1000 h/y)
	Zone 2	Gc	A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapor or mist is not likely to occur in normal operation. (<10h/y)
Dust	Zone 20	Da	A place in which an explosive atmosphere in form of a cloud of combustible dust in air is very likely to occur in normal operation. (>1000 h/y)
	Zone 21	Db	A place in which an explosive atmosphere in form of a cloud of combustible dust in air is likely to occur in normal operation. (10~1000 h/y)
	Zone 22	Dc	A place in which an explosive atmosphere in form of a cloud of combustible dust in air is not likely to occur in normal operation. (<10 h/y)

*IEC : International Electrotechnical Commission
EPL : Equipment Protection Levels

IECEx and ATEX

Technically identical standards for electrical equipment since 2006. For single standards, a single set of tests and assessments can support both IECEx and ATEX. An ATEX EC-Type Examination Certificate can be based on an IECEx ExTR but ATEX documentation dose not necessarily support an IECEx certificate.The technical requirements of a manufacturer's QA system are effectively the same, both are based on ISO/IEC 80079-34 and an IECEx QAR can support the issue of an ATEX QAN.

IECEx for the World - Product certification:

• Aim : One single certificate for any hazardous area product recognized and accepted throughout the world.
• Already accepted in many countries. Alternatively a single test report(ExTR) can be sent to any member certification body(ExCB) to issue locally accepted certification.
• Currently only electrical equipment to IEC Standards (but IEC Standards for non-electrical equipment are being developed).
• ExCB issues an ExTR(covering the product type) and a quality assessment report(QAR) (covering the related production facility)
• Certificates of conformity created directly on the IECEx website, fully visible for the whole world to read and check states.
• ExCB maintains the status of certificate based on the outcome of future QARs, a minimum of 2 audit visits in a 3years period.

 

ATEX for Europe - Conformity Assessment:

• A common approach to lifting barriers to trade within the European Economic Area(EEA).
• The Directive becomes law on implementation in each member country and compliance is mandatory within the EEA.
• Applicable to non-electrical equipment and protective system as well as electrical equipment.
• Certification from a Notified Body is Mandatory for Category 1 and M1 equipment, protective systems and Category 2 and M2 electrical equipment. Otherwise self declaration of compliance is permitted.
• An EC-Type Examination Certificate and Quality Assessment Notification (QAN) are issued by a Notified Body.
• The manufacturer -alone- is responsible for the Declaration of Conformity which must accompany every product which bears the European(CE) Marking.

 

Installation and maintenance in hazardous areas

Installation and maintenance in accordance with IEC/EN 60079-10, IEC/EN 60079-14, IEC/EN 60079-17.

General requirements ( IEC/EN 60079-14 )
Hazardous areas are classified into Zones 0, 1 and 2 for gases and vapours according to IEC 60079-10-1, and into Zones 20, 21 and 22 for dusts according to IEC 60079-10-2 in order to facilitate the selection of appropriate electrical equipment and the design of suitable electrical installations.

Electrical equipment should, as far as is reasonably practicable, be located in non-hazardous areas. Where it is not possible to do this, it should be located in an area where an explosive atmosphere is least likely to occur. Electrical installations in hazardous areas shall also comply with the appropriate requirements for electrical installations in non-hazardous areas. However the requirements for nonhazardous areas are insufficient for installations in hazardous areas. Where additional protection is required to meet other environmental conditions, for example, protection against ingress of water and resistance to corrosion the method used shall not adversely affect the integrity of the equipment. Electrical equipment and materials shall be installed and used within their electrical ratings for power, voltage, current, frequency, duty and such other characteristics where non-conformity might jeopardize the safety of the installation.In particular, care shall be taken to ensure that the voltage and frequency are appropriate to the supply system with which the equipment is used and that the temperature classification has been established for the correct voltage, frequency and other parameters.

Products for use in hazardous areas are commonly designed for IEC standard voltages according IEC 60038. If a supply voltage is outside of these standardized voltages, then equipment should be specially selected and certified. All electrical equipment and wiring in hazardous areas shall be selected and installed in accordance with Clauses 5 to 13 inclusive and the additional requirements for the particular type of protection (Clauses 14 to 23). Installations should be designed and equipment and materials installed with a view to providing ease of access for inspection and maintenance (IEC 60079-17).

Equipment and systems used in exceptional circumstances, for example research, development, pilot plant where explosion protected equipment is not available, need not meet the requirements of this standard, provided that the installation is under the supervision of a competent body and one or more of the following conditions, as appropriate, are met:

• measures are taken to ensure that an explosiveatmosphere does not occur, or
• measures are taken to ensure that this equipment is disconnected before an explosive atmosphere occurs, in which case ignition after disconnection, e.g. due to heated parts, shall be prevented also; or
• measures are taken to ensure that persons and the environment are not endangered by fires or explosions.

In addition, the measures or conditions or control shall be documented by a competent body who:

• is familiar with the requirements for this, and any other relevant standards and code of practice concerning the use of electrical equipment and systems for use in hazardous areas, and,
• has access to all information necessary to carry out the assessment.

 

Marking

ATEX Coding

IECEx/ATEX -equipment marking

NVG / NVIS Compatible Lights

Fire NVG (Night Vision Goggle) Compatible Light

NVG is intended to amplify the minimum amount of light so that objects can be seen at night. However, when the bright light of the luminaries passes through the NVG, it becomes invisible due to the amplification of the light.The NVG filter installed in the NVG compatible light enables the use of NVG by removing the light of the recognized wavelength band of NVG.
The first is to enable the night tactical activities of the NVG users, and the second is to enable the least work of the non-NVG users.
NVG compatible light is required to enable night tactical activities of NVG users and minimal work of non-NVG users.

Classification

Night vision imaging system(NVIS) compatible aircraft interior lighting is divided into the following types and classes.

TYPE I  Lighting compatible with any direct view image NVIS utilizing Generation III image intensifier tubes
TYPE II  Lighting compatible with any projected image NVIS utilizing Generation III image intensifier tubes.
Class A  Lighting compatible with NVIS utilizing 623nm minus blue objective lens filters with the specifications.
Class B  Lighting compatible with NVIS utilizing 665nm minus blue objective lens filters with the specifications.
Class C  Lighting compatible with NVIS having a ‘green leak’.
            This edition of this document assumes that lighting meeting class B compatibility criteria is also compatible with Class C NVIS.

Definition

2-1.Night vision imaging system (NVIS)
Any system that uses image intensifier tubes to produce an enhanced image of a scene in light conditions too low for normal navigation and pilotage.

2-2.Direct view image NVIS (Type I)
Any NVIS that uses generation III image intensifier tubes and displays the intensified image on a phosphor screen in the user’s direct line of sight.

2-3.Projected image NVIS (Type II)
Any NVIS that uses generation III, image intensifier tubes and projects the intensified image on a see through medium in the user’s line of sight. This configuration allows simultaneous viewing of the intensified image and visual cues such as HUD symbology.

2-4.Class A NVIS
Class A NVIS is not compatible with red cockpit lights because of the overlap between the spectrum of red light and the sensitivity of Class A NVIS

2-5.Class B NVIS
A Class B NVIS is compatible with NVIS Red and therefore is compatible with properly filtered red lights and color electronic displays that meet the requirements of Table II,III .

2-6.Class C NVIS
Some aircraft have HUDs that use a hologram as the reflective element in the combining glass. Holograms typically work with only one wavelength of light. This feature can be used to improve the efficiency and see-through clarity of the HUD, but it means the light coming from the HUD is concentrated at one wavelength. since this wavelength is in the green part of the spectrum and is blocked by the minus blue filter in the NVIS, it is nearly impossible to see a holograph HUD with Class A or Class B NVIS. Consequently modified NVIS have been built and tested which have a ‘notch’ or ‘leak’ in the green part of the spectrum The Class C filter is sometimes called the ‘leaky green’filter.

2-7.Compatible interior lighting
The aircraft interior lighting that provides acquisition of aircraft interior information with the unaided eye without degrading the image intensification capabilities of the NVIS during night flight operations. Conforming to the detailed performance and test requirements specified herein shall be considered as meeting this definition

2-8.Secure
An army definition often applied to ground vehicles and equipment meaning that the visible light emitted is reduced to the minimum needed to do the mission and the near IR content is reduced to less than an estimated 5% of the visible light.

2-9.Friendly
Exterior lighting that is fully usable by people without NVIS but has drastically reduced IR content so that it can be used while flying formation with aircraft in which NVIS are being used.

2-10.Covert
IR lights or lights that are typically filtered so they are not visible to the naked eye beyond approximately 20 to 30 feet. These lights may be intended to provide illumination so that NVIS will work without adequate natural light.

Relative spectral response characteristics of Class A,B,C NVIS

This document defines the radiant energy interface requirements and test procedures applicable to NVIS compatible lighting systems for new or modified aircraft lighting equipment and crew stations. Figure is the assumed NVIS spectral response characteristics that shall be used to define NVIS compatibility criteria herein.
Relative spectral response characteristics of Classes A, B and C NVIS

NVIS lighting color limits

The color of illuminated information on instruments, control, control panels, and on illuminated areas in designated crew station and compartment areas shall be as specified herein for that component. These lighting colors and limits are shown on the chromaticity diagram and are designated as ‘NIVS GREEN A’, ’NVIS GREEN B’, ’NVIS YELLOW’, ‘NVIS RED’, ’NVIS WHITE’

Conformance to these colors and color limits is determinated by the following formula(u’- u1)2 + (v’- v1)2 ≤( r ) 2
where ;u’and v’ = 1976 UCS chromaticity coordinates of the test article
       u1’ and v1’= 1976 UCS chromaticity coordinates of the center point of the specified color area
       r = radius of the allowable circular area on the 1976 UCS chromaticity diagram for the specified color

CIE 1976 UCS Chromaticity Diagram

NVG compatible and incompatible lighting relative to the NVG response

A complication is the existence of different ‘classes’ of NVG, which refers to the exact response bands of the devices. Class A NVGs have a response that starts at around 625nm and extends to about 930nm, while Class B NVGs respond in the range 655nm to 930nm.
These wavelengths are controlled by the use of special filters, often referred to as ‘ minus blue’ filters, mounted on the front of the NVGs.

NVG compatible green & red lighting and Class A & B NVG response

One effect of this is that it is harder to make lighting compatible with Class A NVGs than Class B.
Indeed red lighting can not be used successfully in a cockpit with Class A NVGs.
MIL-STD-3009 takes account of these two classes in defining colors and levels of compatibility.
They relative responses of Class A and Class B NVGs, with NVG compatible green and red light outputs superimposed.

NVG compatible & NVG friendly light relative to NVG response

Whereas internal lighting is generally required to be very compatible, with negligible impact on NVGs, external lighting needs Lighting needs to be visible, both through NVGs and to the naked eye, in order to perform its intended function of providing awareness of position and direction of flight.
This means there has to be a greater degree of overlap between the emissions and the NVG response, but not so much that the NVGs are degraded -a balance is required where an NVG friendly light output is compared with an NVG compatible source, relative to the Class B NVGs response

MIL-STD-3009

TABLE III. NVIS radiance requirements(metric units)

NOTE1. For these lighting components. Class B equipment shall meet all Class A requirements of this specification.
The relative NVIS response data for Class A equipment. GA(λ) (TABLE III.a.). shall be substituted for GB(λ) to calculate NVIS radiance.

TABLE III.a. NVIS radiance requirements using English units

Where :
NRa = NVIS radiance requirements for Class A equipment.
NRb = NVIS radiance requirements for Class B equipment.
fL = footlamberts

NOTE1. For these lighting components, Class B equipment shall meet all Class A requirements of this specification.
The relative NVIS response data for Class A equipment. Ga(λ) (TABLE III.a.). shall be substituted for Gb(λ) to calculate NVIS radiance.

IP and IK Classification

IP CLASS

IP (Ingress Protection) classification tells us the product capability to avoid ingress from water or solid objects. The first number refers to solid objects/dust and the second to water. DAEYANG has laboratories for testing IP classification. Mainly, higher IP-rating means higher dust and watertightness.

IP protection degrees for enclosures

Degrees of protection against solid foreign objected by the first characteristic numeral.

First characteristic numeral : Protection against solid bodies

First characteristic numeral : Protection against solid bodies

IP	Tests	Description	Definition
0		Non-protected	-
1		Protected against solid foreign objects of50mm diameter and greater(accidental contact with the hand)	The object probe, sphere of 50mm diameter,shall not fully penetrate(The full diameter of the object probe shall not pass through an opening of the enclosure.)
2		Protected against solid foreign objects of12.5mm diameter and greater(finger of the hand)	The object probe, sphere of 12.5mm diameter,shall not fully penetrate(The full diameter of the object probe shall not pass through an opening of the enclosure.)
3		Protected against solid foreign objects of2.5mm diameter and greater(tools, wires)	The object probe of 2.5mm diametershall not penetrate at all(The full diameter of the object probe shall not pass through an opening of the enclosure.)
4		Protected against solid foreign objects of1mm diameter and greater(fine tools, small wires)	The object probe of 1mm diametershall not penetrate at all(The full diameter of the object probe shall not pass through an opening of the enclosure.)
5		Dust-Protected(no harmful deposit)	Ingress of dust is not totally prevented, but dust shallnot penetrate in a quantity to interfere with satisfactoryoperation of the apparatus or to impair safety
6		Dust-tight	No ingress of dust

Second characteristic numeral : Protection against liquids

Second characteristic numeral : Protection against liquids

IP	Tests	Description	Definition
0		Non-protected	-
1		Protected against verticallyfalling water drops	Vertically falling drops shall have no harmful effects
2		Protected against verticallyfalling water dropswhen enclosure tilted up to 15°	Vertically falling drops shall have no harmful effectswhen the enclosure is tilted at any angle up to 15°on either side of the vertical
3		Protected against spraying water	Water sprayed at an angle up to 60° on either side ofthe vertical shall have no harmful effects
4		Protected against splashing water	Water splashed against the enclosure from anydirection shall have no harmful effects
5		Protected against water jets	Water protected in jets against the enclosure from anydirection shall have no harmful effects
6		Protected against power water jets	Water protected in powerful jets against the enclosurefrom any direction shall have no harmful effects
7		Protected against the effects oftemporary immersion in water	Ingress of water in quantities causing harmful effects shall not be possible when the enclosure is temporarily immersed in water under standardized conditions of pressure and time
8		Protected against the effects oftemporary immersion in water	Ingress of water in quantities causing harmful effects shall not be possible when the enclosure is temporarily immersed in water under standardized conditions of pressure and time

IK Number

This standard refers to the classification of the degrees of protection provided by enclosures against external mechanical impacts when the rated voltage of the protected equipment is not greater than 72,5 kV.This standard is only applicable to enclosures of equipment where the specific standard establishes degrees of protection of the enclosure against mechanical impacts.

IK Number

IK	Tests	Impact Energy (joules)	Equivalent Impact
0		Non-protected	No Test
1		0.15	Drop of 200g object from 7.5cm height
2		0.2	Drop of 200g object from 10cm height
3		0.35	Drop of 200g object from 17.5cm height
4		0.5	Drop of 200g object from 25cm height
5		0.7	Drop of 200g object from 35cm height
6		2	Drop of 500g object from 20cm height
7		3	Drop of 500g object from 40cm height
8		5	Drop of 1.7kg object from 29.5cm height
9		10	Drop of 5kg object from 20cm height
10		20	Drop of 5kg object from 40cm height