Number nine Tank House: the Jubilee glassworks 100m south west of the Government Offices on Chalon Way


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:


Ordnance survey map of Number nine Tank House: the Jubilee glassworks 100m south west of the Government Offices on Chalon Way
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The building or site itself may lie within the boundary of more than one authority.

St. Helens (Metropolitan Authority)
National Grid Reference:
SJ 51220 94993

Reasons for Designation

Glass has been produced in England since the Roman period, although field evidence is scarce until the late medieval period. Wood was the main manufacturing fuel up to the early 17th century, so the industry was located in woodland areas, particularly the Weald. From about 1610, production shifted to the coalfields. Glass production requires three major components: silica, alkali and lime, together with colouring material for certain products and decolourisers for clear glass. Lead was also used in the production of certain types of glass during the Roman period and after the 17th century. The manufacturing process involves three stages, fritting, melting and annealing. Fritting was a common practice before the 19th century involving heating the main glass constituents to produce an unmolten material for grinding, melting and annealing. Melting involved the remelting of previously formed glass, and the production of new glass from raw materials. Until the late 19th century, glass was normally melted in pre-fired crucibles of refractory clay, on stone benches called sieges, within the melting furnace. Use of coal as the preferred fuel and automatic bottle-making machinery in the 1880s led to changes to the melting furnaces and the use of larger furnaces, hitherto conical structures over circular furnaces. Regenerative furnaces were developed in the 1860s, and tank furnaces for bulk melting quickly followed. Flat-glass production methods were made obsolete by the Pilkington float-glass system of 1959. The third process is annealing. Because the rapid cooling of molten glass can give rise to internal stresses, glass was treated in furnaces designed to heat the glass to a point where deformation begins, then cooled gradually. In the 19th century conveyors were introduced to take glass through a hot zone into cool air. Features on glass manufacturing sites include various types of furnaces, producer-gas plants for the making of gas from coke at 19th century glassworks, bottle-making machinery, blowing irons or pipes for blowing glass, glass residues and various buildings used as stores or warehouses. A total of 135 glass production sites (representing about 25% of the estimated national archaeological resource for the industry) have been identified as being of national importance. This selection, compiled and assessed though a comprehensive national survey of the glass industry, is designed to represent the industry's chronological depth, technological breadth and regional diversity, and to include all the better preserved glass sites, together with rare individual component features.

The Number nine Tank House is the best surviving example of a late 19th century glassmaking tank furnace building in England, comprising the building, its cone and furnace. In addition there are the well-preserved remains of the system of flues to bring in gas from the supplier. The building now forms the centrepiece of a museum devoted to the glass industry. It has been extensively excavated under modern conditions, repaired and the outside features consolidated. In addition, many features have been added to the display to give a comprehensive picture of the glassmaking process in operation at the time of its foundation. The glassworks is of prime importance in the historical development of the technology of glassmaking and its status as a museum gives it a very high value for education and recreational enjoyment at the heart of a regeneration scheme for the town centre.


The monument includes a brick-built glassmaking factory known as a tank house, with a conical flue, containing the remains of a Siemen's regenerative tank furnace dating from the late 19th century. It was set up in 1889 by Pilkingtons the family of glassmakers, and continued in use until 1920. In the history of glassmaking in Britain, this furnace represents a radical departure from traditional glassmaking techniques. The glass was formerly melted in large pots which were built inside a furnace and as each pot became exhausted, another was built in its place. In a Siemen's furnace the glass was melted in a brick-lined tank and was continuously fed with material and continuously drawn off as required. A second innovation in this design was the reuse of the heat used in the melt with a resulting saving of fuel.

The tank was fuelled by a mixture of gas and air, heated before introduction into the furnace, and this heat was reused to warm firebricks in an underground system of flues before re-entry to the furnace. The glass which was produced in this process was in the form of large (up to 2.5m long) blown cylinders which were then cut, flattened and polished to produce large glass sheets.

The building which housed this process is known locally as the `Hotties'. From the outside the building is rectangular, with a truncated cone protruding through the centre of the roof. The walls are buttressed on the long sides. It measures approximately 23m by 11m and stands 8m high. Inside it is the cone, made of brick, on steel girders, supported by cast iron pillars. The brick cone was constructed so that the base is square, rising to an oval at the top. This cone is a survival of a traditional form and has the benefit of deflecting some of the waste heat from the furnace back down to the metal (molten glass) below. Beneath the cone are the remains of the tank furnace, and on either side was a swing chamber for the glass to be gathered (tapped on a blowpipe) and blown into shape before being cut and flattened into plates.

Only the eastern chamber survives, since the area on the western side was modified for later use as storerooms. Arches on each of the short walls provided ventilation for the workers in the chamber and were bricked up or unbricked according to the temperature outside. Beneath this tank there are brick-vaulted tunnels to bring in gas and air from the southern side of the building.

Outside the building, on the southern side, archaeologists have exposed the tunnels through which coal gas was brought from the supplier to the furnace. Immediately adjacent are the remains of a coal mine pit head and cage shaft which were in use before the glass works were built. This pit was used to provide coal for firing the earlier conventional furnaces which were the mainstay of the glass industry on this site before the adoption of the Siemen's furnaces in 1883. The Tank House is Listed Grade II*.

The abutments of a modern footbridge and the modern portico leading into the building, the surface of all footpaths around the site and the cast- iron water pipes and their fittings on the canal side are excluded from the scheduling, although the ground beneath these features is included. Fixtures and fittings not original to the Tank House or its period of use are also excluded.

MAP EXTRACT The site of the monument is shown on the attached map extract.


The contents of this record have been generated from a legacy data system.

Legacy System number:
Legacy System:


Books and journals
Barker, T C, The Glassmakers, (1977)
Lancaster University Arch Unit, , The Hotties, (1994)
Singleton, D, Glassmaking Cones in St Helens, (1976)
Lancaster Univ Arch Unit, Survey Reports, (1994)


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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