Standards bring order to chaos

Implementation of the New Sampling/Sensor Initiative (NeSSI) standards will simplify sample system design, installation and operation, fundamentally changing and improving the way we do process analysis.

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Dan HebertBy Dan Hebert, PE, Senior Technical Editor

DO YOUR process analyzer tubing installations look like a bowl of spaghetti that someone accidentally dropped on the floor? Is every installation different, depending on which tubing and fittings were used and how they were installed?

The New Sampling/Sensor Initiative (NeSSI) will address these issues by simplifying and standardizing sample system design. NeSSI also will adapt the emerging class of lab-on-a-chip sensors to a miniature/modular smart manifold with the aim of fundamentally changing and improving process analysis.

NeSSI is a non-affiliated international ad hoc group, including such end users as Dow Chemical, ExxonMobil and UOP. Leading vendor members include ABB, Circor Tech, Emerson Process Management, Parker-Hannifin, Siemens and Swagelok.

NeSSI operates under the sponsorship and umbrella of the Center for Process Analytical Chemistry at the University of Washington in Seattle. NeSSI’s membership focuses on manufacturers supplying parts and components for the initiative, as well as end-users doing in-house testing.

Meanwhile, the U.S. Food and Drug Administration’s (FDA) Process Analytical Technology (PAT) initiative promotes the use of analytical and other process sensing systems to improve manufacturing processes in regulated industries. End users want NeSSI and PAT to induce manufacturers to produce standard sampling, sensing and analyzing systems with interchangeable components.

According to Patrick Lowery, chief engineer at Circor Tech, end user benefits from NeSSI and PAT are extensive. Standardization allows end users to select from a handful of different suppliers for various functions with mix-and-match and plug-and-play capabilities because all surface-mount components are designed with the same footprint. These systems have a significantly smaller footprint, so about 50% less system area is needed. Reduced internal volume and smaller wetted-surface areas allow for shorter purge times and less probability of cross contamination from one analytical sample run to the next. There also is less propensity for corrosion and surface phenomena, such as contaminate adsorption/desorption, thanks to this reduced surface area.

In addition, there’s no need for end users to employ expert tube benders. No unique brackets are needed for each manufacturer’s sensing components, which are presently required with tube-and-fitting sample conditioning systems. Likewise, the requirement for thread tape and the current multitude of fitting varieties to connect classic multi-vendor components is virtually eliminated. Sealing integrity is greatly improved, and leak event frequency has been shown to be virtually non-existent in more than 200 Circor Tech and Parker Hannifin models installed in the field during the past four years. Also, better sealing yields lower maintenance costs, higher safety standards, and less fugitive emissions.

Steve Doe, analytical market manager at Parker Hannifin, says his firm has been actively developing advanced functionality for its NeSSI platform of IntraFlow products for more than two years. Parker’s block heaters are placed in direct contact with the back side of the system backplane to conductively heat the system, as opposed to traditional convective heating arrangements.

Parker’s double-block and bleed-stream switching is also available, as well as pressure and differential pressure sensors inferring flow characteristics to provide remote feedback capabilities. “These additional functionalities provide a fully integrated pressure, temperature, and flow control and monitoring package”, claims Doe.

Another leading NeSSI vendor is Swagelok. “Our MPC platform eliminates most of the tubing and fittings normally used in assembling traditional sample system panels,” says Dave Simko, Swagelok’s marketing resources manager. “The only tubing and fittings needed are those few connections required to install the platform into the complete process analyzer system, and to connect support systems for stream selection, calibration, purge and carrier.”

Simko adds, as FDA’s PAT guidance is implemented, there will be many applications for NeSSI systems. “PAT was promulgated in its final form in September 2004, and the pharmaceutical manufacturers are determining which analytical techniques and methods are most applicable to their specific processes. Some applications have already been implemented,” reports Simko.

The primary objective of NeSSI is to reduce cost. Specifically, its goals are to reduce the cost of designing and building process analyzer systems by 40%, and to cut the cost of owning these systems by 35%. Simko says end-users already are reporting savings along those lines.

Savings accrue from reduced design time, faster assembly, easier installation, and reduced testing and commissioning time. Shorter sample transport lines also reduce both cost and lag time.

NeSSI systems use less analyzer gas, reducing the cost of consumables. These systems also have increased response time and analyzer uptime.

“The next step for end users and process analytical OEMs is to integrate these systems with process analytical devices to create a complete integrated solution,” adds Lowery.

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