Open Forum

The first of these is prevailing wind directions. Meteorological data is available for most parts of the country, and in coastal areas the prevailing winds can blow for up to 40% of the year. If such winds are significant, then it would be reasonable, if there is a choice, to set the tanks in line across the wind rather than in line with it.

The second aspect is the land type major monitor which has been developed in recent years as a tank fire fighting weapon. With the tanks set down as previously mentioned, advantage can be taken of the wind. This holds good for tanks protected by fixed foam pourers, since in a fire one or more of the pourers might be damaged in which case a monitor could make up the deficiency.

Some information on the location of a major monitor related to tank height is essential before such layouts can be made. There is little information so far from the manufacturers, although it is hoped that it will be forthcoming in the near future.

Where there are numbers of tanks of varying sizes in the same enclosure it is generally economic to group the smaller tanks together. By doing so a safer layout can be achieved as an intermediate fire wall can be raised to enclose them to contain spillage up to the capacity of one tank if desired thus avoiding putting the larger tanks in the group in jeopardy.

5S'x30'

30'X30' qo' so' -I-I-I-!

Figure 5

140' RADIATION 4000 aTh.u/sa/FT/HR 190' I BOUNCARV 1_1_1_1_1_1 __ 111_1_

Fire Walls and Means of Escape The only way to fully understand the implications of the new Code with regard to the height of fire walls is to work out some examples using the recommendations set out in

WHITHER BASEEFA Petroleum licensing authorities must be among the best 'Clients' of BASEEFA if 'client' is the right word to describe ?n authority which is content to accept the Service's certIficates. Many petroleum licensing authorities are members of the Association for Petroleum Acts Administration. What then is more sensible than that BASEEFA should be offered the opportunity to report its activities through the columns of the "Bulletin"? th It is true that a licensing authority not only determines e :xtent of 'danger areas' within its jurisdiction but also the types of 'safe' apparatus which it will allow those areas. Nevertheless BASEEF A would be failing in function if it. did not advise the authority ?n the. type f apparatus whICh the Service regards as bemg SUItable Or the various danger areas. it, such as the net area of the enclosure of 100,000 sq. feet given in paragraph 2.2.2(f).

If a single tank of 60,000 or 120,000 water tons capacity is considered and the enclosure· is designed to hold the contents of the tank with the permitted net area maintained, then the walls would be so high that they would cost a fortune since the retaining structure would have to be made in concrete to obtain stability. This problem is at present theoretical for most of the industry, but it will arise in the not too distant future.

If the total storage of 60,000 water tons is split into two tanks in the same enclosure and the same restraints applied, then the fire walls are still very high. In some cases it will be found to be more economical to increase the size of the enclosure and reduce the height of the fire walls to say 8 feet, so that they can be formed from cheap materials which are available locally, and to insert between the tanks intermediate fire walls.

High fire walls have many disadvantages apart from cost. They can deflect the wind so that its dilution effect at the floor of the enclosure starts at a distance between three and six times the height of the wall from its base. The possibility of an accumulation of vapour in the still air areas cannot be ignored. High walls also add to the difficulties of fire fighting and access together with means of escape.

Access to the enclosure is required for normal routine work, and this access forms the first means of escape. If this is the man's usual way of entering the enclosure it is logical to attempt to locate the foot of the tank stairway at the shortest distance from this point. If a man travels the route regularly he could subconsciously know the direction to be taken in an emergency. Alternative means of escape should be provided within 150 and 200 feet of the foot of the tank stairway.

It would be so easy to take the figures and recommendations set down in Part 2 Section 2 of this Model Code and to apply them rigidly, conveniently forgetting that this is a guide. It is to be hoped that this contribution may help in some small way towards the practical application of this section of the Code which is of interest to us all.

It is alleged that standards are being prepared by the Service which do not indicate to what type of 'danger area' they relate. If this is true, does it not show a lamentable breakdown in communications?

Rumour has it that some difficulty is being experienced with the new BASEEFA petrol pump code and this again may be the result of poor communications. From an authority's point of view the only pump which requires special certification is one which has within its housing components which are not separately certified as being flameproof intrinsically safe. Moreover, full certification of a pump IS not necessary if the only non-flameproof or non-intrinsically safe component is one which is constructed to a comparable foreign standard having BASEEFA blessing for use in petrol pumps generally.

BASEEF A's purpose is to aid both industry and enforcing authority. To this end information should be disseminated and discussion encouraged. So far as petroleum licensing authorities are concerned, is this not what the "Bulletin" is all about?