EC9811 ozone photometer

The EC9811 Ozone photometer meets U.S. EPA requirements for an ozone primary standard (SRP) and an ozone transfer standard.

The EC9811 utilises the Beer-Lambert law and UV absorption detection to measure the ozone output concentration and automatically correct for gas temperature/pressure changes. Concentrations can be displayed in units of ppm, ppb, μg/m³ or mg/m³

General Downloads

Brochure - EC9811 ozone photometer

Customer Downloads (must be logged in)

Service Manual - EC9811 ozone photometer

Communicator software - EC9800

The following is extracted from the U.S. EPA Transfer Standards for Calibration of Air Monitoring Analyzers for Ozone Technical Assistance Document a link to the original document is below.

About Transfer Standards

In ambient air monitoring applications, precise ozone concentrations called standards are required for the calibration of ozone analyzers. Ozone standards cannot be stored for any practical length of time due to the reactivity and instability of the gas. Therefore, ozone concentrations must be generated and “verified” on site. When the monitor to be calibrated is located at a remote monitoring site, it is necessary to use a transfer standard that is traceable to a more authoritative standard.

A transfer standard is defined as a transportable device or apparatus which, together with associated operational procedures, is capable of accurately reproducing pollutant concentration standards or of producing accurate assays of pollutant concentrations which are quantitatively related to a higher level and more authoritative standard. The transfer standard’s purpose is to transfer the authority of a Level 1 pollutant standard to a remote point where it is used to verify or calibrate an air monitoring analyzer.

The US EPA is attempting to reduce the number of common terms that were used in the past such as: primary standard, local primary standard, transfer standards and working standards that sometimes have been the cause of confusion.

This document will identify the family of standard reference photometers (SRPs) as Level 1 standards. Beyond the SRPs, all standards will be considered transfer standards and will be numbered (starting with 2) based on its “distance in the traceability chain” from a verification against a Level 1 standard. With each additional level, the number of standards available is multiplied. Each standard is traceable through a chain of “higher” standards to the Level 1 standard.

Transfer standards fall into two main categories:

1. Analytical Instruments

This category employ an instrumental technique to assay stable, flowing O3 concentrations. The analytical instrument must be capable of measuring O3 concentrations adequately over the concentration range of interest, using a well-defined chemical or physical property of O3. Examples of transfer standards using an instrumental technique would include almost any commercial O3 analyzer designed for ambient air monitoring, or any other O3 analyzer that can measure O3 concentrations suitably in the appropriate concentration range. (note: Modified versions of Serinus 10, EC9810, EC9810B or EC9811 fulfills this purpose)

The analytical instrument itself can only assay existing O3 concentrations. When used as a transfer standard to calibrate an O3 monitor at a field site, some additional means must be provided to generate the O3 concentrations: usually, a UV O3 generator, an air pump, and an ambient air scrubber to provide clean zero air. (note Ecotech's GasCal 1100GPT fulfills this purpose).

The authority of the transfer standard is clearly contained in the verification of the analytical instrument. The O3 generation components could thus be considered incidental to the use of the transfer standard. Some advantages may therefore be obtained by equipping each field site with its own O3 generation system – which might also double as a zero-and-span system – and transporting only the analytical instrument from site to site.

2. Generation Devices

Transfer standards in this category are simply devices that generate accurate O3 concentrations without having any capability to assay the generated concentration output. The accuracy of these devices depends entirely on their inherent generation stability and reproducibility under changing conditions of use. The most common example of a generation device is the UV (photolytic) O3 generator. (Note: Ecotech's GasCal 1100GPT meets this criteria).

Recommendations on Use of Specific Types of Transfer Standard Devices

Due to the advances in ozone monitoring technology, many of the newer transfer standards include both generators and photometers. Therefore, it is strongly suggested that:

• Level-2 standards and/or standards used in the verification of other transfer standards include both a generation device and a photometer. (EC9811)

• Level-3 standards be, at a minimum, a photometer. (Serinus 10, EC9810, EC9810B). The level 3 standard can be a photometer and generator (EC9811 or GasCal 2000) but should not be just a generator.

• Level-4 and greater can be a ozone generation device. (eg GasCal 1100GPT)

Calibration Frequency of Ozone Transfer Standards

Regional Standard Reference Photometer - once per annum

Ozone Level 2 Transfer Standard - once per year or after repair

Ozone Transfer Standard Level 3 and greater - At beginning and end of ozone season or every 6 months whichever is less.

Ecotech is able to offer a Level 2 or greater ozone calibration service.

The full USEPA document can be obtained below

USEPA Transfer Standards for Calibration of Air Monitoring Analyzers for Ozone Technical Assistance Document