View report page

34
photographic processing works. The iron sulphide was formed by the interaction of
photographic chemical solutions with an iron drain-pipe.
Advice was given in some cases as to whether proposed new discharges were
acceptable, or whether some form of pre-treatment would be necessary.
Safety
The Spiralarm lamps used in the main drainage service to give warning of potentially
dangerous atmospheres were periodically overhauled and adjusted in the laboratory
and finally tested by exposing them to the atmosphere of a test chamber containing
measured concentrations of inflammable gas. Another type of lamp, the Ringrose,
was also used to some extent and similarly maintained. Sets of self-contained oxygen
breathing apparatus adopted as standard for an emergency were available, and advice
was given as required on their use.
Ventilation
The question of ventilation received much attention particularly in view of complaints
from certain places of emanations. A working group on ventilation was
consequently set up by the Council in conjunction with the Metropolitan Boroughs
Standing Joint Committee and the Chemist-in-Chief was a member. As a result of
its recommendations the Council decided to seek additional powers of control of trade
discharges by means of clauses in a forthcoming General Powers Bill, and also to initiate
experiments to secure increased ventilation by removing interceptors.
Paints and surface coalings
During the year under review the new paint laboratories (rooms 623 and 624) were
equipped and put into service. Some difficulties were encountered, not the least of which
was to maintain the work output whilst testing the new equipment and adopting new
quantitative standards without vitiating comparison with results previously obtained.
Troubles experienced with the plant and its installation in a small compass were overcome
by the maintenance architects and engineers and to both of these branches of the
service grateful thanks are due. When the laboratories were officially opened some two
dozen press representatives attended and articles appeared subsequently in many
technical and general journals. Considerable interest has been shown by paint manufacturers
and complete agreement with the Ministry of Supply methods of examination
has been maintained. In addition to accelerated weathering tests which form a valuable
' sorting ' basis, panels are exposed on the roof so that the shorter term tests can be
correlated with long period exposure to London's atmosphere.
The interdepartmental paint committee (chairman the Chemist-in-Chief) has
held four meetings during the year and the sub-committee (chairman the deputy
chemist) met eleven times. The former was concerned with matters of policy whilst the
latter dealt, in detail, with the many problems encountered.

When unsatisfactory paint is found on the site as the result either of complaint or
of the normal examination of site samples an unopened makers' can is requested and
tested. If the complaint is confirmed the manufacturer is asked as a warning measure to
attend a discussion on the matter and if complaint is again made and justified the brand
is struck off the approved list. Ten manufacturers have been cautioned and one brand
deleted during the year. Many painting troubles occurred for which the paint manufacturer
should not be blamed and the following causes have been found—failure to