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Last edited 13 Dec 2018
Instrumentation for critical healthcare environments
Today’s hospitals contain many critical environments where building services play an important role in the wellbeing of patients, staff and visitors. Even the best-designed and built facility will need initial commissioning and constant monitoring to ensure peak performance throughout its lifecycle. Accurate, fit-for-purpose fixed and portable measurement instruments are required in most departments of a hospital, from the boiler room to the pharmacy to ensure that all areas are functioning correctly.
In the wards and operating theatres it is imperative there can be no spread of infections or exposure to potentially hazardous materials. Providing this effectively in terms of equipment ease of use and efficiently both in terms of the cost of instruments and the cost of staff presents challenges to the building services engineer, laboratory or medical personnel. In an isolation facility, for example, staff need to monitor the pressure between rooms (positive or negative) to stop the spread of infections either to or from the patient, the temperature within the protected space, supply or extract ventilation rates, the quality of the air in terms of particulate concentration, as well as the flow-rates of medical gasses. Where, all of theses parameters can be measured with fixed (built-in) devices or portable (hand held) instruments. Measurements of surface contamination may also need to be ascertained for infection control, but these are normally undertaken using standard laboratory techniques.
A number of medical facilities have incinerators on site to dispose of locally-generated clinical waste; many different types of fixed measurement instrumentation are used on every aspect of the incineration process from the temperature thermocouples within the primary incinerator, through to the gas and particulate emissions measurement at the end of the process. To compliment the fixed instrumentation, a selection of portable instruments are also often maintained to crosscheck and temporarily replace the fixed range of measurement equipment should a problem occur.
The boilers that supply steam to the hospital require various types of instrumentation to run correctly, hydrometers for example are used to measure the total dissolved solids (TDS) within the boiler water. If the TDS level rises too high then this can cause foaming and carryover to the steam main leading to contamination of control valves, heat exchangers and steam traps.
There are also water supplies that have to be considered, and the need to combat the possibility of Legionnaires’ disease by chlorine dosing the systems to ensure all of the water pipes are disinfected. The water quality then has to be sampled periodically with the appropriate instrumentation to ensure the water is fit for use.
BSRIA has been working on solving building services design, installation, commissioning and operating problems in hospitals for many years and is only too aware of the importance of correct measurement. Most of the published work however concerns the facilities themselves rather than the instrumentation used for measuring performance. A well-designed facility that has been built and commissioned correctly should be a safe environment to work or visit from day one of its operation.
But, if the wrong instruments are used during commissioning or routine monitoring it could have life and death consequences, as there is the risk of spreading potentially infectious or hazardous agents. In the field of pressure measurement there is a large array of instruments that measure this physical parameter, but if an instrument is used with an accuracy based on its full-scale deflection, not on the indicated value, at low pressures it is impossible to establish if a system is operating correctly. In a surgical suite it may be required to operate at a pressure differential between rooms of 10 Pa. If an instrument with a range of 2000 Pa is used with a manufacturer’s claimed accuracy of ± 0.5% fsd (full scale deflection), there can be an error of some ±10 Pa. This error being almost double the required measurement. Similarly, when measuring air flow rates in a biological flow cabinet, instruments with a typical accuracy of ± 1.5% mv, +0.2 m/s (measured value) can be used. But if the target measurement value is only 0.5 m/s, this accuracy equates to a possible reading as low as 0.29 m/s being accepted which could be very problematic in a critical environment and potentially expose an operator to hazardous materials.
Understanding manufacturers’ claimed instrument accuracies is only part of the problem in the correct selection of pieces of instrumentation; the correct calibration of the equipment is equally vital to ensuring reliable data. For measuring pressures as low as 10 Pa in the surgical suite, the hospital engineer or laboratory staff needs calibrations with an uncertainty of no more than 0.1Pa, which often exceeds what manufacturers are offering. The building services engineer must look beyond the simple requirement of measuring pressure, and understand the details of the complete process. Understanding the real technical merit of an instrument therefore must have a greater significance in the future as services in healthcare facilities become more critical.
When buying, or hiring, instruments the engineer now has a global choice as to which product will meet today’s challenging testing environments. Calibration of this instrumentation is, and always will be, of paramount importance to users, but what is available, especially in changes of technology and the scope of instrumentation available, must also be considered during the selection process. Tests that often took hours to conduct can now be undertaken easier, faster, and more accurately than those taken years ago. For example, there are pieces of instrumentation that can fit test N95 respirators and masks to protect workers against airborne biohazards such as TB or even SARS. Likewise, there are new types of ultrafine particle counters that can be used to trace air pollutants in operating theatres, as well as being used for checking the integrity of filter seals within laboratory fume cabinets.
With such a wide range of instruments available to today’s healthcare professionals they need to look beyond any procurement source that is tied to an individual manufacturer to obtain the best pieces of instrumentation within the marketplace. Equally, staff at the suppliers have to understand the finer points of the instruments they offer, including calibrations at the ranges to be used.
Equipment can, where applicable, include data damping, backlit displays, self-calibration check tools, data logging, keypad lock out to unauthorised users and long life battery operation to name just a few options that can also influence a final purchasing decision.
BSRIA Instrument Solutions is a leading supplier of specialist test and measurement instruments since 1990. It has built its reputation by providing the most reliable and advanced test equipment from leading manufacturers, supporting it with a high level of customer service and technical support to meet with its client’s requirements and expectations. They are able to offer a choice of test equipment solutions with products from many leading instrument manufacturers.
This article was written by Alan Gilbert, General Manager of BSRIA Instrument Solutions department. It was originally published by BSRIA on 28 November at: https://blogs.bsria.co.uk/2018/11/28/instrumentation-for-critical-healthcare-environments/
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