Health & Safety 45


• Background surveys • The potential for immediate intervention


• Targeting control measures on tasks with the greatest exposure potential


• Task mapping (concentration profiles in real-time)


• Checking performance of control measures e.g. filter performance


• Indoor air quality assessments


To improve the accuracy and correlation with gravimetric samplers size selective adaptors may be used and work done by the HSL to compare concluded that: “the Microdust Higgins– Dewell cyclone adaptor measurements agreed closely with the reference respirable concentration for all dusts, whereas those for (competitive devices) were different to the reference….whereas the Microdust CIS (Conical Inhalable Sampler) adaptor underestimated the inhalable concentration compared to the reference.”


Real-time direct reading methods will continue to evolve as the technology changes to meet customer expectations for increasing granularity of data on which to make better decisions as organisations look to comply with legislation but generally improve the safety health & wellbeing of their employees in the workplace within a Corporate Social Responsibility agenda.


Case Study Comparison of Portable, Real-Time Dust Monitors Sampling Actively, with Size-Selective Adaptors, and Passively


The performance of three, portable, real-time dust monitors was investigated inside a calm air dust chamber for a range of industrial dusts and two sizes of aluminium oxide dust.


The instruments tested were the Split 2 (SKC Ltd), Microdust Pro (Casella Ltd) and DataRam (Thermo Electron Ltd), which sampled either passively or actively by connecting a manufacturer supplied, size-selective adaptor and an air sampling pump to the inlet of the monitor.


Two size-selective adaptors were tested with the Split 2: the GS-3 cyclone adaptor and the Institute of Occupational Medicine (IOM) inlet with porous foam inserts. Similarly, two size-selective adaptors were tested with the Microdust Pro: the Higgins–Dewell cyclone adaptor and the conical inhalable sampler (CIS) adaptor with porous foam inserts. The DataRam was tested with a GK 2.05 cyclone adaptor since there was no porous foam adaptor available.


The instruments’ responses were compared with the reference dust samplers: Casella Higgins–Dewell cyclone for the respirable fraction and IOM sampler for the inhalable fraction. The response of the dust monitors was found to be linear with respirable dust concentration when operated either passively or actively using the cyclone size-selective inlets. Their responses were lower when operated actively with the cyclone adaptors compared to the passive operation and lower still when used with the porous foam inserts. There was also often more scatter in the porous foam measurements, attributable to variable clogging of the foams caused by inconsistent loading with dust. The dust monitor responses were sensitive to changes in particle size when operated passively but much less so in active mode with the cyclone adaptors. The Microdust Higgins–Dewell cyclone adaptor measurements agreed closely with the reference respirable concentration for all dusts, whereas those for the DataRam GK 2.05 and Split 2 GS-3 cyclone adaptors were different to the reference. Concentrations measured with the foam adaptors were considerably lower than both the reference cyclone samplers and the dust monitor cyclone adaptors and increasingly under sampled as they became loaded with dust. Inhalable dust measured with the Split 2 IOMadaptor agreed closely with the reference IOMinhalable samplers, whereas the Microdust CIS adaptor underestimated the inhalable concentration compared to the reference.


Andrew Thorpe and Peter T. Walsh


Remote Mountable Flow Meter for Hazardous Locations


The future-ready ST100 Series Thermal Mass Air/Gas Flow Meter from Fluid Components International (FCI) (USA) is now available in a remote mountable configuration, ideal for applications in hazardous areas or hard-to-reach locations.


Remote mount flow meters are ideal for equipment crowded plants or hazardous factory areas where combustible or toxic gases may be present near the


transmitter’s electronics. The ST100’s remote mount transmitter, with optional digital display, can be mounted up to 1000 feet (300 meters) away from the flow sensor using interconnecting cable.


Setting a new industry benchmark for process and plant air/gas flow measurement instrumentation, the revolutionary ST100 Series Flow Meter offers the most feature-rich and function-rich electronics available today. FCI’s ST100 offers superior flow sensing performance to deliver unsurpassed adaptability and value, meeting plant gas flow measurement applications for today and tomorrow.


The ST100 Flow Meter continuously measures, displays and transmits the industry’s most extensive array of parameters. It is available with 4-20 mA analog, frequency/pulse, alarm relays or digital bus communications such as HART, Fieldbus, Profibus or Modbus. The ST100 Flow Meter adapts as necessary to plants’ changing needs or desire for upgrades with a plug-in card replacement that can be changed out by plant technicians in the field, taking “never obsolete” to a whole new level.


The ST100 Flow Meter is user-friendly and versatile, storing up to five unique calibrationgroups to accommodate broad flow ranges as well as differing mixtures of the same gas and multiple gases, obtaining up to 1000:1 turndown. The optional, patent-pending SpectraCal™ Gas Equivalency calibration method lets users select and switch between 10 common gases. The ST100’s standard on-board data logger features a removable 2-GB micro-SD memory card capable of storing 21 million readings.


ST100 Series Flow Meters can be calibrated to measure virtually any process gas including dirty, wet and mixed gases. The basic insertion style air/gas meter measures flow from 0.25 to 1000 SFPS (0.07 NMPS to 305 NMPS) with accuracy of 0.75 percent of reading, 0.5 percent of full scale.


ST100 Series Flow Meters are designed for rugged industrial process and plant environments, including service up to 850 F (454 C). The ST100 is agency approved for hazardous environments, including the entire instrument, the transmitter and the rugged, NEMA 4X/IP67 rated enclosure. Instrument approvals (submitted and pending) include: FM and FMc: Class 1, Division 1, hazardous locations, Groups B, C, D, E, F, G; ATEX and IECEx: Zone 1, II 2 GD Ex d IIC T4.


Reader Reply Card No. Reader Reply Card No. 186 www.envirotech-online.com IET May / June 2012 187


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