The Picric Acid Expense Store To The West Of The Northern Magazine Section, Rotherwas Industrial Park

This is an expense store built around 1916 for the storage and distribution of picric acid, used in manufacturing explosive shells during the First World War. The site architect was JF Milne and the contractors were James Mowlem Ltd.

Structure and Construction

The building consists of a range of 32 individual cubicles, each measuring five feet wide and seven feet deep. The end walls and partition walls are constructed of nine-inch brickwork, as is the lower body of the range beneath the floor level of the cubicles and walkway. The cubicles themselves have wooden framing clad with external clapboarding, with a central door on both the front and rear elevations.

A covered walkway with a miniature railway formerly existed on the east side. Though the floorboards and metal rails have been removed, the brick and timber supports remain in place. A wooden railway platform that once projected approximately eight feet from the west side, supported on brick piers, has been entirely removed. The roofing is corrugated asbestos sheet, with square-plan asbestos vents topped by pyramidal caps.

Exterior Features

The east elevation is divided into bays by square brick piers. Between these piers, corrugated metal walling approximately four feet high forms the balustrade of the former walkway. The east and west walls of the cubicles are essentially identical in design. Each cubicle has four panes of glass in the upper sections of both front and back walls, with electric lighting brackets mounted on the exterior to shine through the windows and illuminate the interior.

The doors were designed without latches but featured a leather closing strap and a lock. A spring mechanism attached to the brick partition walls prevented doors from blowing shut. Several cubicles are now missing their doors, though elements of the closing mechanism survive on others.

The roof extended outwards on the east side to form part of the covered walkway system that connected different buildings across the factory site. Although the wooden flooring and metal lines of the Decauville light railway have been removed, the supporting brick and timber structures remain in place.

Interior

The walls are lined with Uralite (asbestos) sheeting, over which sized and painted canvas is glued. Angled wooden battens finish the corners. Each cubicle has an asphalt floor with a drain in the corner.

Design and Function

This is the one surviving range of expense stores from the two originally on site. Each cubicle was designed to store a maximum of 3,000 pounds of explosive. The design was specifically intended to direct the force of any explosion upwards and outwards, rather than sideways to other compartments, thereby protecting adjacent storage areas.

Map evidence shows the range was originally flanked on its east side by an earth traverse, which has since been removed.

Alterations and Condition

The building has undergone some alterations, including modifications to the dividing walls between individual cubicles. At the south of centre, ten dividing walls project above the roof line to their original height. On either side of this section, other dividing walls have been reduced in height. The building has suffered the loss of some doors and panels of clapboarding on both fronts. A fire at the southern end has caused damage and the collapse of the roof structure to three cubicles.

Historical Context

British failure at the Battle of Neuve Chapelle in 1915 was widely reported in the press, with The Times reporting in May 1915 that "The want of an unlimited supply of high explosives was a fatal bar to our success". The ensuing 'shells scandal' contributed to the collapse of Asquith's Liberal Government and prompted a reappraisal of arms production. The new coalition government appointed David Lloyd George to head a new Ministry of Munitions, which enacted a series of laws including the Munitions of War Act of 1915. This legislation exerted greater control over existing factories and enabled the creation of National Factories, of which Rotherwas was one.

In June 1916, the Ministry of Munitions purchased a 545-acre site at Rotherwas to build a munitions factory. The site was divided into two sections: to the north of the road and railway was the section for filling shells with picric acid (also called Lyddite), and to the south was the Amatol section (a TNT mixture). Production targets were set for filling 400 tons of lyddite each week and 700 tons of amatol, with storage capacity for six weeks of production.

The northern (lyddite) section was itself divided into two parts, each a mirror image of the other. The first filled shells were produced in November 1916.

The volatile nature of explosives meant strict rules applied to site access and prevention of contaminants. Picric acid was delivered to the site and stored in bond stores at a distance from the production huts, in open ground with earth traverses on the side nearest the filling sheds. From these bond stores, the acid was moved to 'expense' stores just prior to being used for the filling process.

The empty shell stores and the ranges of picric acid stores were the largest buildings on the First World War site. Other work, such as sifting and melting the picric acid and filling shells, was done in wooden huts or small brick sheds with corrugated iron roofs. These were connected by wooden walkways raised above ground level, roofed with corrugated iron and incorporating metal tracks for small-gauge railways.

Over a million shells were filled with lyddite at Rotherwas during the First World War. In common with other munitions factories, large numbers of women were employed on the site handling dangerous materials. The improvement in production of TNT-based explosives led to the gradual reduction and eventual suspension of lyddite shell production in April 1918. However, following the explosion at Chilwell, Unit 2 of the section was re-opened in August 1918, and Unit 1 was converted to charging shells with mustard gas in October of the same year. This later use required alterations to the internal layout of the filling houses, but the site was apparently not otherwise altered.

At the end of the First World War, the site was mothballed by the government. Following the 1935 general election, the factory was reactivated as part of the general drive towards rearmament. With the exception of the empty shell stores, picric acid stores and transit sheds, all of the First World War buildings were demolished and replaced by new sheds surrounded by concrete blast shelters. There were twenty-four of these buildings which filled cartridges with cordite and connected these with shells filled with explosives from the southern section to form quick-firing ammunition, though their function was adapted as the war progressed to include filling torpedoes and 25-pound shells.

By July 1940, the northern assembly section employed 2,100 people. Both the empty shell store and the picric acid stores appear to have been used during the Second World War; the empty shell store on the northern section was preparing 3.7-inch anti-aircraft shells for filling in 1940, and there is anecdotal evidence that the picric acid stores were used for defusing faulty ammunition.

Following the Second World War, parts of the factory site were converted to use as an industrial park. The eastern empty shell store was demolished between 1946 and 1961. The northern factory site was purchased from the Ministry of Defence by Hereford County Council in 1973. The previous year they had bought a small piece for a new sewage works, which has since been greatly expanded, resulting in the demolition of two of the picric acid bond stores. The Hereford to Ross railway closed in 1964, and in 1974 the wooden buildings inside the blast walls of the north section were demolished.