Report on failed Bass bottle
August 11th, 1995
Prosyma Research Ltd report to Weltonhurst Ltd.
S F Bush with J D Tonkin
Introduction
Weltonhurst supply high density polyethylene blow moulded containers to Richard Millington and Co Ltd. In use, the containers are filled with cleaning fluid for cleaning out beer lines. The containers are pressurized to 20-35 psi approximately, and remain in use for some years.
Depending on size of container, the safe working pressure (SWP) is given(1) as 40-60 psi. The cleaning fluids are specified by the brewers such as Bass. The Bass cleaning fluid specification is(1):
Sodium Hydroxide: 9.2 ± 1 gm/litre
Sodium Hypochlorite: 7.6 ± 2 gm/litre
“Phosphorus butane carboxyl”: 4.8 ± 0.25 gm/litre
To-date the long term effect on the bottles of these cleaning fluids has not been assessed.
Over the last few years about one bottle a year has been sent back to Millingtons(2) having failed. It is thought that all the identified failures were five or more years old. Failure has usually been in the form of a crack, but recently a 50 litre six-year-old bottle has completely disintegrated. It is this particular failure which has prompted the present investigation.
References
1: Richard Millington Ltd, Product Specifications issued by D Turner, 8.7.92
2: D Turner to SFB Telecon, 10.8.95.
3: P Burrows to SFB, Atochem data sheet, fax 24.7.95