Prest-O-Sales and Service, Inc. distributes products that have been developed to meet the stringent requirements of each specific environmental application. Our vendors manufacturing and certification specifications meet industry standards as well as federal, provincial, state and local regulatory requirements.

A variety of calibration mixtures are designed specifically for environment applications and available in the following grades:

• NIST-Traceable Reference Materials (NTRM) Grade -- Produced by Praxair and certified by the National Institute of Standards and Technology (NIST) and accepted by the Environmental Protection Agency (EPA) as the highest-accuracy commercial standards available.
• EPA Protocol Grade -- Used to calibrate and audit CEMS, Praxair's EPA Protocols are NIST-traceable with an accuracy of ±1% and manufactured according to the latest EPA methodology.
• Research Gas Materials (RGM) Grade -- Provides government, industry and quality processes with an additional NIST-traceable standards source. Produced in cooperation with NIST to establish NIST traceability for gaseous components where there are no existing NIST Standard Reference Materials (SRM).
• Primary Master Grade -- Components are weighed into the cylinder using weights traceable to NIST and directly certified against NIST-traceable laboratory standards.
• Micro-Blend Grade -- Direct gravimetric capillary blending for VOC components. This technique eliminates sequential methods for producing part-per-billion or part-per-trillion mixtures of organic compounds. Standards are prepared in cylinders using Praxair's Vapor Deposition Inerting (VDI) cylinder treatment process and certified by mass spectroscopy and gas chromatographic techniques.
• Dynamic-Blend Master and Standard Grades -- Zero blend batch preparation tolerance. Two to 100 cylinders can be produced with virtually the identical concentration.
• Certified Standard Grade -- Components are introduced into the cylinder by partial pressure or manometric methods and certified against NIST-traceable or Praxair internal laboratory standards.
• Non-Certified Standard Grade -- Suitable for applications that do not require an analytical certification.
• Benchmark Standard Grade -- Sulfur dioxide, nitric oxide, carbon monoxide, carbon dioxide, oxygen and hydrocarbon mixtures are produced on Praxair's dynamic blending systems to match the nominal concentration you order. Our dynamic blending capabilities allow Praxair to provide replacement standards that are the same concentration as the standards ordered previously, certified to ±2% accuracy and NIST-traceable.
• Mobile Source Products -- NIST-traceable mixtures to meet California's Bureau of Automotive Repair and EPA specifications which contain carbon monoxide, carbon dioxide, propane and nitric oxide in high-pressure and non-returnable cylinders.
• Safety and Industrial Hygiene Products -- Cost effective portable and high-pressure cylinders provide an easy, accurate and safe monitoring process.