P.F. Nolan

An analysis of fatal unintentional dwelling fires investigated by London Fire Brigade between 1996 and 2000

Abstract London is a large capital city with a population of approximately seven million people. It shares many problems with other large cities around the world, including deaths due to fire. Many of these fire deaths can be linked to social problems such as poor housing, loneliness, illness, etc. Data from the London Fire Brigade Real Fire Library—a unique database of information collected from real fire incidents by dedicated teams of fire investigators operating in the Greater London Area has been used to obtain a range of statistics about fatal fires and fire death victims for the 5-year period from 1996 to 2000. Most deaths occurred in unintentional dwelling fires. The statistical information has therefore been analysed to identify the main factors involved as to why people die in unintentional dwelling fires and see what lessons can be learnt from these deaths. Common risk factors identified in the unintentional dwelling fire deaths investigated include smoking, alcohol, old age, disability, illness, living alone, social deprivation and not having a working smoke alarm fitted. Comparisons are also made with the results found from other studies and measures for preventing unintentional dwelling fire deaths are examined.

Discussions on the use of fine water sprays or mists for fire suppression

Abstract Recent experimental work on fine water sprays indicates that they may have a wider application in the fields of fire extinction and combustion suppression than previously anticipated. In this paper, the means of producing fine sprays are briefly examined and the major results of some case studies are reviewed. A few unexpected positive results have come to light, especially with regard to using fine mists to protect against fires involving live electrical equipment. However, it is still premature to advocate the use of fine sprays for many applications.

Fires in workplace premises: risk data

Abstract London is a capital city with a population of seven million people. It shares many problems with other cities around the world, including the risk of uncontrolled fires in workplace premises. In order to provide an effective assessment of fire risk in the workplace and help London Fire Brigade to devise a suitable inspection programme for the implementation of fire precaution regulations, quantitative information on the likelihood of fires occurring in different types of workplace premises is required. Such information has been obtained from London Fire Brigades Real Fire Library (RFL)—a unique database of information collected from real fire incidents by dedicated teams of fire investigators operating in the Greater London area. This paper presents an analysis of fire probability and risk data for London, quantifying the likelihood and associated risk of fires occurring in different types of workplace. The data collected in the RFL is also used to identify the most common fire scenario characteristics occurring in each type of workplace.

Review of the selection and design of mitigation systems for runaway chemical reactions

Abstract The chemical and pharmaceutical industries employ many exothermic reactions, and loss of control can lead to thermal runaway. Although control systems are becoming more and more sophisticated, vent systems are still commonly employed. In future years, the increase in environmental issues is likely to outlaw direct atmospheric venting, and there remains the need for passive mitigation of runaway reactions and vented materials. Various options are discussed, including inhibition, quenching of the reactants and separation of the liquid and gas phase before further treatment or venting. Advantages and disadvantages are given. Various currently available design methods are given for separation vessels and quench systems.

Evidence of the oxidation of deposits in heated bitumen storage tanks

Abstract Thermal analytical techniques have been used to examine the exothermic nature of the deposits found in heated bitumen storage tanks and to determine if they could act as an ignition source to flammable vapours. The deposits were found to undergo an oxidation/smouldering reaction at temperatures found on the underside of the roof of the tanks. Onset temperatures for exothermic behaviour ranged from 337 to 406 K. Deposits taken from refinery tanks were found to have an activation energy in the range of 80–90 kJ mol −1 . The self-heating found in deposits constitutes a smouldering reaction which could deplete the oxygen concentration and so contribute to the conditions suitable for the formation of pyrophoric material. In a situation where cross-ventilation can occur and air is allowed to pass over the surface of the deposits, the rate of reaction would increase leading to higher temperatures and increasing the risk of fire.

Study of iron sulfide as a possible ignition source in the storage of heated bitumen

Abstract It is thought that pyrophoric iron sulfide may be able to form in heated bitumen storage tanks and act as a source of ignition to the flammable vapours in the ullage space. Electron microscopy has been used to indicate the possible presence of pyrophoric material within a sample of bitumen deposit taken from a refinery tank. High levels of sulfur were found in areas rich in iron and part of this sulfur was in the form of a sulfate, a product of the weathering of pyrite. The sulfur found in the iron-free areas of the deposit was in the form of elemental sulfur.

Cleaning metal components after the Montreal Protocol : Introductory review

Until recently, the manufacturing and finishing industries have placed heavy reliance on the use of pure methyl chloroform or chlorofluorocarbon solvents to achieve acceptable levels of cleaning or precleaning of metal components. Much effort has been devoted since the signing of the Montreal Protocol to finding replacement cleaning agents for these and other banned or controlled substances and it is now clear that a variety of different cleaning processes must be developed. In the long term it is likely that the vast majority of industrial cleaning will be carried out in aqueous solutions making it necessary to investigate the special problems involved in cleaning difficult components. A review, which summarises the issues and current problems being encountered in the search for replacement cleaning processes, is presented. Also considered are the relevant techniques and experimental procedures which can be used to investigate surface cleanliness and related phenomena.

Fundamental study of generation of interfacial temperatures with metal surfaces and coatings under conditions of sliding friction and mechanical impact

Abstract The measurement of surface temperatures generated by sliding friction is discussed and experiments are carried out using dynamic thermocouples to determine surface temperatures arising from sliding friction and mechanical impact. Experimental results over a very wide range of loading and velocity conditions show an appreciable degree of similarity with calculated values using the equations given in part one of this study. Impacts with a 7·3 kg projectile with nickel and nickel coated test heads onto an angled steel anvil, have shown that very high transient surface temperatures can be reached. At velocities above 5 m s−1, surface temperatures in excess of 1000°C are obtained within a contact duration of less than 2 ms. The lower temperatures recorded in the case of impacts involving nickel plated steel test heads correspond to the temperature difference across the thickness of the coating rather than to the difference in surface temperature and the cold junction.

Fundamental study of generation of interfacial temperatures with metal surfaces and coatings under conditions of sliding friction and mechanical impact Part 1 - Thermal analysis and theoretical evaluation of surface temperature

Abstract A study has been carried out to evaluate the surface temperatures reached on sliding metallic surfaces over a wide range of conditions. This is of interest for a number of reasons, including determining the conditions of mechanical sliding friction which might be associated with failure or loss of adhesion of a coating intended to prevent galling or seizure and establishing the likelihood of igniting any pyrophoric substances present on the surface. In Part 1 of the study, the uncertainties involved in determining the surface temperature are considered and a thermal analysis performed to illustrate how variations in the properties of the contacting surfaces, together with the loading and sliding conditions influence the surface temperature. A numerical analysis of the heat transferred into the bulk of the metal indicates that in many cases the generated temperature increase will significantly decay over a comparable depth to that of an engineering metal coating.

Case histories of incidents in heated bitumen storage tanks

Abstract A study has been made of 73 case histories of incidents involving heated bitumen storage tanks. The majority of incidents were found to be due to operations such as charging and discharging of tanks, including overfilling which can lead to lagging fires and exposure of heater tubes. A number of incidents were the result of spontaneous ignition or unknown causes: it is proposed that regular cleaning of tanks would reduce the number of these incidents.