The performance of cooling and ventilation (CV) equipment is defined as its availability to the PS, SPS and LEP accelerators. Three teams for the accelerators plus a Utilities team, which receives performance information from the physics and technical control room, carry out the operation of this equipment. Collected performance statistics as well as data from the Computer Aided Maintenance Management system (CAMM) and supervision system provide information on the exact state of the CV equipment. This is used to more effectively schedule preventive maintenance which, by reducing system failures, results in improved equipment performance. This paper will present performance data and discuss the prospects for improving it through the use of an updated version of CAMM and a new supervision system

Monsted, A

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EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCHORGANISATION EUROPÉENE POUR LA RECHERCHE NUCLÉAIRECERN - ST DivisionPresented at the 3rd ST WorkshopChamonix, France, January 25 - 28, 2000CERN-ST-2000-031February, 2000PERFORMANCE REPORT ANDIMPROVEMENTS IN CV MACHINE AREASA. MonstedAbstractThe performance of cooling and ventilation (CV) equipment is defined as its availability tothe PS, SPS and LEP accelerators. Three teams for the accelerators plus a Utilities team,which receives performance information from the physics and technical control room, carryout the operation of this equipment. Collected performance statistics as well as data from theComputer Aided Maintenance Management system (CAMM) and supervision system provideinformation on the exact state of the CV equipment. This is used to more effectively schedulepreventive maintenance which, by reducing system failures, results in improved equipmentperformance. This paper will present performance data and discuss the prospects forimproving it through the use of an updated version of CAMM and a new supervision system.21 INTRODUCTIONThis paper will describe how the Cooling and Ventilation (CV) group is evaluating the performanceof equipment belonging to the group. The functioning of a major part of the CV equipment isimportant for the accelerators and a breakdown in a small piece of equipment can cause aninterruption of the experiment. Therefore the availability of the CV equipment for physics is the mostcrucial factor for the CV performance. The performance statistics are compiled by the control rooms,and include the number of hours of experiment running, interruptions of the experiment, and whichpiece of the group's equipment is causing the downtime. The Prévessin control room within the SLdivision is responsible for the experimental machine operation of the LEP and SPS accelerators. ThePS accelerator is operated by the main control room in Meyrin within the PS division. These data areused to calculate the CV equipment performance. The Technical Control Room is responsible for thesurveillance of the equipment belonging to the CV group in the accelerators, and on the basis of thedaily reports the equipment causing the stop can be determined.To avoid equipment breaking down the preventive maintenance is of the utmost importance.For this purpose the new Computer Aided Maintenance Management system (CAMM), that is goingto be put into service in 2000, will be a greatly improved tool for the operation teams and themaintenance contractor. Another important step is the upgrade and standardization of the supervisionsystem.2 PERFORMANCE STATISTICS2.1 Data presentedThe following four sets of data are used to define the performance of the CV equipment:- number of times during the year when a failure in the CV equipment has caused an interruption ofthe experiment;- total number of hours of downtime registered by the physics control rooms caused by CVequipment;- CV equipment downtime compared with the total hours of downtime for all the servicesregistered;- number of hours of interruption caused by CV equipment compared with the total number ofhours of experimental runtime; this is equal to the availability of the CV equipment.2.2 PS statisticsThe statistics from the lepton and proton periods constitute the PS data, Fig. 1 [1]. These statisticsalso include linac data.Figure 1: PS statistics.H ours  o f C V  s tops  in  P S2520.579 .50204060801001997 1998 1999YearHoursH ours  o f downtim e caused by C V  equip. Availability and downtime for PS4.1%7.1%3.4%98.9%99.0%99.1%99.2%99.3%99.4%99.5%99.6%99.7%99.8%1997 1998 1999Year 0.0%1.0%2.0%3.0%4.0%5.0%6.0%7.0%8.0%Availability of CV equipment for physicsCV equip.downtime / total hours of downtime3It is normal practice in the physics control rooms for all downtime hours due to coolingproblems to be registered in the account of the CV group. However, some of these cooling problems,such as water leaks in the magnets or in electrical cabinets, are the responsibility of other groups. Insuch cases, the number of downtime hours not caused by CV equipment should be transferred to thegroup responsible. This is done in the SL control room for the LEP and the SPS, but has not been thepractice in the PS control room. This results in the number of interruptions attributed to the CV groupbeing too high: In 1999 the PS operation team attributed only 25 hours of downtime to CV equipment,equalling only 23% of the hours in the account.2.3 SPS statisticsThe statistics from the lepton, proton and ion periods constitute the SPS data, Fig. 2 [2].Figure 2: SPS statistics.The downtime in 1999 can be divided into four types.- Equipment failures caused four incidents, 44% of the total hours. After each incident the causewas examined and improvements made ensure more reliable operation of the equipment and toprevent similar incidents.- Failures by the maintenance personnel caused one incident, 12% of the total hours. This incidentand two similar ones at the LEP have led to a change in working practice. Now only maintenancewhich can be done with zero risk of stopping the experiment is carried out during the run.- Start-up problems after electricity saving days (EJPs) caused two incidents, 44% of the totalhours. There were several EJPs during the ion period. After each EJP the CV equipment is startedup immediately before the start-up of the experiment. This means that even small problems in thestarting phase immediately cause downtime for the experiment. This procedure has now beenchanged: The equipment is now started up from 1800 to 2200 hours and possible problems can besolved before the start of the run at 0100.2.4 LEP statisticsThe LEP is the last stage in the chain of accelerators delivering a beam. Downtime for the PS and SPSwill immediately affect the LEP. However the amount of downtime registered for the CV group isonly for failures caused by LEP equipment, Fig. 3 [2].N um be r an d  hou rs  o f C V  s tops7.59 .611 .802468101997 1998 1999YearNumber02468101214HoursN um ber o f s tops  caused  by C V  equ ip .H ours  o f downtim e caused by C V  equ ip .Availability and downtime1.32%1.41%1.30%99.7%99.8%99.9%1997 1998 1999Year1.2%1.3%1.4%1.5%Availability of CV equipment for physicsCV equip.downtime / total hours of downtime4Figure 3: LEP statistics.In 1999 the high demand for physics and the continued increase of the beam energy pushed allsystems to the limits. This caused more downtime for all services, but a record number of 4971physics hours were achieved.2.5 Utilities statisticsFor the physics control rooms there is no difference between the different teams in the CV group andso the utilities team is not registered separately in the statistics. However it is a very important teambecause it is responsible for delivering water to the accelerators. In 1999 a stop at Pumping Station 5caused 10 hours of downtime in the LEP, 10 hours in the SPS and 7 hours for the PS.3 MAINTENANCE STRATEGIES3.1 CV equipment conditionsThe CV equipment for the LEP, SPS and PS was installed when the accelerators were constructed.Fortunately the equipment installed for the accelerators has proven to be of good quality and has beenwell-maintained, thus limiting the number of breakdowns. However, when a breakdown does occurspare parts are often no longer available from the supplier. This makes intervention very costly andthe delivery of parts can take months. Thus it is important that all crucial equipment has a standbysystem so interruptions can be avoided.Each piece of equipment is registered in the CAMM database. The data stored include technicalinformation, time periods between maintenance, and the kind of work which needs to be carried out.This system is an important tool for maintenance work. Unfortunately the structure of the databaseand the user interface is not kept up-to-date, which currently limits the value of the system.3.2 Preventive maintenanceFrom a maintenance point of view the equipment belonging to the CV group can be divided into twomajor categories. One category can be maintained during operation of the experiment and a second,the crucial equipment, can only be maintained during a shutdown because a failure duringmaintenance work could cause a stop to the experiment. To categorize the equipment a risk evaluationis carried out for all equipment, defining when maintenance work can be carried out. The shutdownperiod is being reduced by the growing demand of physics. This factor, along with an increasingamount of critical equipment given by the risk evaluation, is causing a demand for more manpowerfrom the maintenance contractor during the shutdown. This exceeds the number of people necessaryduring the run. For this reason it is difficult to fulfil all the maintenance work that has to be doneduring the shutdown.Number and hours of CV stops07.51101231997 1998 1999YearNumber024681012HoursNumber of stops caused by CV equip.Hours of downtime caused by CV equip.Availability and downtime0.0%2.9%2.0%99.6%99.7%99.8%99.9%100.0%100.1%1997 1998 1999Year0.0%0.5%1.0%1.5%2.0%2.5%3.0%3.5%Availability of CV equipment for physicsCV equip.downtime / total hours of downtime5Some equipment installed today needs no or very little preventive maintenance. An exampleof this type of equipment is the compressors for the water-cooling units. These units are constructedto operate for 10–15 years with very limited maintenance. After this period machines can beoverhauled or replaced. These machines have successfully served the LEP experiment and are nowreplacing all CV water-cooling units. In the design phase of à new cooling installation, equipment thatrequires less maintenance should be preferred if the economic and technical aspects for two brands ofequipment are equal.3.3 Interventions in case of breakdownsSince the risk of equipment breaking down can never be avoided the efficiency of the on-call serviceis very important. The ability to intervene quickly and effectively can minimize the minutes ofdowntime. The on call service is included in the maintenance contract and the persons on call stay athome [3]. Outside normal working hours the time between a problem occurring and the arrival of theon call service can be up to one hour. This ability to intervene also depends on the technicalknowledge of the personnel. Especially for the old installations, where documentation on theequipment is sometimes lacking, familiarization with the equipment is very important. For the PS andSPS in particular on-call personnel appear to lack technical knowledge and require more training. Forthe SPS between 1 October and 30 November 1999, the on-call service needed to call a member ofthe operation staff in six out of seven interventions outside normal working hours.4 FUTURE IMPROVEMENTSTo improve the CV performance the equipment has to be monitored carefully. With the new CAMMthe historical figures can be viewed [4]. For instance the number and type of interventions can be usedto calculate a figure for the cost of maintenance for specific equipment. Based on this figure, a cost-based analysis to determine if the equipment should be replaced or repaired can be carried out. This isnot possible with the current version of CAMM. Moreover the existing structure of the data is notgood, thus making it difficult to compare similar types of equipment. Along with the update, arestructuring of equipment data allows better search possibilities and more efficient access to the data.The monitoring system, which is currently managed by several systems, will be replaced [5]. Inthe future all these systems will be integrated into a single system using fieldbus technology. The datawill be transferred to standardized software for supervision (WISCON), which allows the operationteams to improve their function of system control. This standardization allows a lot more informationfor each station on the accelerators to be transferred to the operation teams. For example, it would bepossible to constantly monitor the vibration of the water pumps, indicating whether the pump needs tobe renovated. This would give time to take action before the equipment breaks down, thus preventingphysics downtime.5 CONCLUSIONTo enable intervention to take place before equipment breaks down CAMM and WISCON should beused to their full potential. At the division level a big effort is invested in these systems to get thestructure in place. Thereafter the operation teams will optimize the maintenance routines in order tohelp the contracting company to carry out the proper interventions.Moreover, equipment which needs little or no maintenance during its lifetime should bechosen, lowering maintenance costs and freeing more resources for updating equipment. Whenbreakdown occurs the downtime period should be limited through an on-call service which is able tointervene quickly and efficiently.6REFERENCES[1] PS division operation statistics, retrieved from: CERN divisional data/PS division/PSoperation/Operation statistics.[2] SL division operation statistics, retrieved from: Srv2_home\div_sl\STAT\.[3] Call for tenders IT2204/ST, Maintenance operation and Minor installation work for CERNcooling and HVAC systems.[4] L. Annila, Future objectives by maintenance management in the CV group, Second STWorkshop 1999.[5] R. Bartolome, P. Ninin, P. Sollander, R. Martini, B. Vercoutter, M. Trebulle, TCR industrialsystem integration strategy, Second ST Workshop 1999.

Performance Report and Improvements in CV Machine Areas

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