LPGVent Sizing of explosion relief vent areas

GUIDELINES ON THE APPLICATION OF DIRECTIVE 94/9/EC OF THE EUROPEAN PARLIAMENT AND THE COUNCIL OF 23 MARCH 1994 ON THE APPROXIMATION OF THE LAWS OF THE MEMBER STATES CONCERNING EQUIPMENT AND PROTECTIVE SYSTEMS INTENDED FOR USE IN POTENTIALLY EXPLOSIVE ATMOSPHERES

News letter ESMG april 2009

Venting devices are commonly used to try to reduce the damage caused by any dust explosion that may occur in silo systems. In North America and Europe the sizing of these vent areas is governed by standards NFPA 68 and EN 14491, respectively, both of which have recently come into force. The aim of the present work was to compare these standards in terms of the cost of protecting against dust explosions. Vent areas calculated according to NFPA 68 were smaller than those calculated in line with EN14491, except when the silos had a length/diameter ratio of 1, when the opposite was true. The difference increases for high length/diameter ratios, especially when the reduced explosion pressure is low. The optimum design for attaining minimum protection costs according to the two standards was slightly different. As a practical example, the cost of protecting a real silo using venting panels was calculated using both standards.

Many materials handled within the Food Industry have flammable or explosible properties but their hazards are often overlooked as they are considered ‘everyday’ products. These materials may be used in either powder or liquid form and can be produced naturally or chemically. Published data indicates that the Food Industry experiences more recorded explosions than any other segment of industry with over 30% of all reported incidents involving food or animal feed.

Do you know the thermal limits of your materials? Almost all materials will undergo some form of thermal oxidation, decomposition or self-reaction at elevated temperatures. It is therefore a prerequisite of safe chemical manufacture and processing that the thermal stability limits of the materials are understood when working at elevated temperatures.

Static electricity continues to cause problems when handling and processing powders. Although costly in terms of production figures many problems, such as powders sticking to surfaces, are often simply lived with in the mistaken belief that nothing can be done. However, if the risk is one of fire and explosion, as is often the case, doing nothing is not an acceptable option. This document provides some basic background information on the issues and offers a structured approach to assessing the likely problems and hazards for a particular process. Clearly in such a short article we cannot cover all eventualities and in many situations it will be crucial to seek expert advice.

Presentation By Martin Gossenwinkel INBUREX at Barcelona ATEX A FACT seminar

On 1 July 2003, in Spain, the Real Decreto 681 / 2003 became enforceable and binding on all new industrial establishments with a risk of explosive atmospheres. As from 30 June 2006 it also became enforceable for all industrial establishments with a risk of explosive atmospheres. As a result of this new legislation all these establishments are now bound to draw up an explosion protection document. By Xavier de Gea LPG

A self-combustion characterisation index based in thermogravimetric and differential scanning calorimetry techniques.