DNH Ex loudspeaker specifically designed for hazardous areas
The DNH Ex loudspeaker products are designs engineered and manufactures in Norway supplying some of the world's largest range of Ex rated horn ceiling speaker, voice alarm, atex speaker, cabinet speaker,ex speaker, loudspeakers, sold around the world through distributors, your contact in Australia for DNH is Morrison’s Public Address. In addition to DNH strong position in the petroleum, hazardous areas industrys DNH is known for its ability to tailor products according to the clients demands and to supply on time.
Flammable gases, mist and dust, together with Oxygen, form explosive atmospheres. If such an atmosphere is ignited, it will result in an explosion, which can in turn cause serious damage to personnel and equipment.
An explosion can only take place if the following factors are in place simultaneously:
Flammable substance (gas, vapor, mist or dust) in a suitable distribution and concentration, Oxygen Ignition source
An explosion atmosphere only occurs if the substance to air ratio lies within a certain range, the explosion limits. The explosion limits depend on the ambient pressure and the oxygen concentration of the air.
In order to avoid explosions and associated hazards, an operator must incorporate effective ant-explosion measures into their plant/operating area. The principle of integrated explosion requires that explosion protection measures are taken in the following order:
Measures to prevent formation of a dangerous explosive atmosphere.
Measures which prevent dangerous explosive atmospheres from igniting.
Measures to restrict the effects of a possible explosion to a safe level
These principles in turn have appropriate actions to be taken:
Primary explosion protection, meaning all measures which prevent the formation of an explosive atmosphere.
Secondary explosion protection, meaning all measures which restrict the effects of an explosion to an insignificant level
Explosion resistant protection, meaning all measures taken to reduce the effects of an explosion to an insignificant minimum.
Classification of Zones
Hazardous areas are classified into Zones, depending on the composition and presence of an explosive atmosphere. This enables both selection of suitable equipment and appropriate electrical installation. Electrical apparatus for use in hazardous areas are divided into various categories. The additional character G for gas or D for dust specifies whether the electrical apparatus may be installed in gas and dust endangered areas.
Zones according to EC directive 991921EG:
Zone 0: Continuous presence of explosive atmospheres, device requires very high level of protection.
Zone 1: Occasional presence of explosive atmospheres, device requires high level of protection.
Zone 2: Infrequent presence of explosive atmospheres, device requires normal level of protection.
DNH Loudspeakers classified for both Zone 1 and 2 (visit for more details)
IP Ratings Explained:
IP is short for International Protection, also interpreted as Ingress Protection Rating, and is defined by international standard IEC 60529. It classifies the degree of protection provided against the intrusion of liquids, solid objects, dust, accidental contact, and water in electrical enclosures. The two digits indicate conformity with the conditions summarized in the tables below. Where there is no protection rating with regard to one of the criteria, the digit is replaced with the letter X. The first digit represents the protection against solid objects and dust, while the second digit represents the protection against water and other liquids.