Data recording in the new environmental laboratory
The new environmental test complex is named after the late Dr Trevor Gooch (see Connect March/April 2005 issue). It comprises seven individual laboratories and a control room, covering a total floor area of about 350m 2 . In addition to a wide range of tests in sour and sweet environments to support the oil and gas industry it embraces several types of static and dynamic environmental test including salt spray, creep testing ofplastics in hot water and tests on sustained load cracking of titanium alloys in cold seawater.
Ventilation is provided throughout and there are local extraction points, either extracting from permanent enclosures or fume cupboards or available where required via flexible hoses. Ring main supplies of N 2 and H 2 S gases have been installed, and disposal of test gases is also via a central collection system, which pipes them to activated carbon filters, and the main ventilation stack.
A sealed drainage system has been provided, and test solutions can be pumped directly into this, eliminating the risk of out-gassing into laboratory air space. There are fixed hydrogen sulphide monitors throughout the laboratories,linked to controls and alarms in addition to portable monitors.
These features are available in all the laboratories although testing is not restricted to such environments. Wiring has been installed linking each laboratory with the control room, so that computer monitoring and control can becarried out centrally.
Corrosion fatigue is a relatively recent development in sour testing at TWI. Corrosion fatigue testing in other environments, notably seawater with and without cathodic polarisation, has been carried out for many years, andcontinues to take place within the fatigue laboratories.
Such testing in sour environments needs much closer attention to environmental control however, and in particular to control of oxygen level, and also requires all the safety measures associated with hydrogen sulphide. Soservo-hydraulic equipment has been added to the range of static load and screw driven slow strain rate equipment in the sour service testing area.
Using a hydraulic supply, from the main Engineering Hall, four specially designed 500 kN test rigs have been installed for carrying out corrosion fatigue tests on strip specimens in tensile axial loading, as well as three lower loadcapacity servo-hydraulic machines, which are used for fatigue crack growth rate testing.
From the original H 2 S test laboratory, a range of dead weight loading 'A' frames, each with its own load cell, has been transferred, and located in individually ventilated booths. Fume cupboards and hoods have been provided forother bolt loaded, or unstressed exposure tests, and full ring tests. The existing range of 5L autoclaves, and slow strain rate testing equipment has also been installed in an adjacent room.
One of the remaining four laboratories is used for a range of bolt loaded or unstressed tests in a fume cupboard, many of which will use H 2 S. The remaining three laboratories currently house a set of dead weight loaded frames with a chilled seawater system, designed for exploring sustained load cracking in Ti alloys, a salt spray cabinet, and aplastics creep set-up, capable of testing specimens under tensile load in hot water up to 80°C. These tests do not use hydrogen sulphide, but this test space can easily be converted for sour testing.
To learn more, Industrial Members should contact Richard Pargeter. E-mail: richard.pargeter@twi.co.uk
