Review of Dave Mumford's lecture entitled: "Inspection and Integrity of Pressure Plant

Newport & District Materials Society
7 Dec 2015

Inspection and Integrity Assessment of Pressure Plant:  1st December 2015

Only three Committee members and a sprinkling of students turned up for the third lecture of the season suggesting that this might be a low point attendance-wise, but fortunately  Sarah Boad of the Institute and a number of Society stalwarts ensured that respectability was achieved.  Sarah made her usual pitch for new IoM3 members and was rewarded by at least one individual who could be seen completing his application form.  The main event then commenced.  Dave Mumford is a materials engineer who went through the British Steel/ Corus Engineering Doctorate scheme before starting his own business PowerstaQ in partnership with three others. 

As his lecture title suggests the company's expertise is in the inspection and assessment of pressure plant and Dave began by paying an indirect tribute to the 18th century engineer James Watt whose improvements to the steam engine have led to its use widespread throughout the world as a source of power.  Often steam engines are tucked away out of sight, but if they are not properly maintained their subsequent failure can be explosive and fatal.  Dave illustrated this point with several slides showing the result of boiler explosions thus highlighting the paramount need for inspection and certification of pressure plant and the raison d'etre of his company.  He then turned to the metallurgy of water tube and fire tube boilers and potential failure mechanisms in the steels used.  Creep under stress at elevated temperatures, especially in superheaters, often occurs and this may be intergranular or transgranular depending in conditions.  Precipitation strengthening is one commonly used preventative strategy.  Examination of the microstructure is a useful investigative tool and can provide evidence of pearlite degradation whilst graphitisation at relatively low temperatures is another possibility. Fatigue and corrosion in various guises are additional failure mechanisms to be guarded against.  Of course, the human element cannot be discounted and Dave asked his audience what they thought might be the potentially most destructive command ever employed the answer being "Full steam ahead".  Ship's commanders who require the maximum output from their engines at a moment's notice jeopardise the future capability of their vessels, whilst those who neglect to carry our routine maintenance also store up future trouble.  The next series of slides provided graphic illustrations of poor practice. 

One a more positive note, Dave turned to a case study of a project his company had been involved in.   This concerned a system for the floating production storage of oil which acts as a buffer between an offshore well (or wells) and the tankers which later take the crude oil to refineries.  Power is needed to pump the oil around the system and since this system had already been in use for a number of years off the African coast a major inspection and overhaul was necessary before its life could be extended.  This story had a happy ending in that after suitable system mapping and renewal of worn out pipes the refurbished assembly was deemed to have met the required ASME 31.1 standard.  Planned preventative maintenance was therefore shown to be essential to the safe working of power plant. 

At the conclusion Dave answered questions, Sarah fired off a number of tweets and the audience retired satisfied that they had had a constructive evening.