Brooks Instrument”s weatherproof thermal mass flowmeters and controllers now conform to the Ingress Protection (IP) IP66 classification of the International Electrotechnical Commission. This product line includes models SLAMf, MfxxS, Mfxxi, and MfxxX. Brooks was the first mass flow measurement and control provider to introduce a weatherproof/washdown thermal mass flow instrument complying with NEMA 4X/IP65 in 1998. The difference between the IP66 and the IP65 standards for which these products were previously approved is an upgraded waterproofing capability for the housing that encloses the electro-technical components of the Mf Series devices. The IP66 standard tests the device housing to a water velocity twice that of the IP65 standard, displaying the increased capabilities to withstand harsh wash-down environments used in any industry. Another test frequently cited in the flow instrumentation industry, the IP67 standard, is an immersion test and does not test the device with the impact of powerful jets. The IP66 standard is the highest and most relevant standard for flow measurement and control customers who are washing the units down with spray jets. Both the mass flow product itself and the NEMA 4X certification that it carries remain unchanged on the Brooks mass flow models. The IP66 update is the result of more rigorous testing procedures that are already encompassed by the NEMA 4X certification. IP66 includes the requirements of IP65 so there is no change necessary for customers with existing documentation requiring the IP65 standard. The IP66 classification used most often by European customers is now at a comparable level with the NEMA 4X standards generally used by customers in North America. All classifications have complete protection from dust, human/tool contact. Product labels and documentation for the Mf Series devices are being updated to note this upgrade.