Carefully register the location of each steam trap, maybe with the help of existing data. We note all information, like brand, type, usage, etc. During the inventarisation, we already do part of the analysis.  We look for specific problems, like steam- and water shock, wrong dimensions of condensate systems and badly designed pipe configurations, wrong type of steam trap, etc.. The first inspection is usually the most difficult and time consuming one. Steam traps are preferably indicated on a floor plan.

The registered information is kept in a database. A correct build-up of the measuring database is necessary for the execution of reliable measurements.

Next to being inspected as to being operational, also an inspection is needed of the leaks of flange connections, setup and the right application for this type of steam trap, mounting error, external steam leaks, opened bypass taps, etc.

Because of the many variables in a steam system, for example back pressure, a temperature measurement alone is not the most reliable indicator. A visual inspection of steam traps with atmospheric drainage is also not reliable because visible steam plumes can be created because of revaporised condensate, caused by the pressure difference over the steam trap. The most reliable measurement is the combined temperature/ultrasound measurement.

The after-inspection report is the instrument for a proactive and cost-conscious policy. With a good report, the person responsible can make an action plan, based on facts.

Before deciding on a monitoring technique, it is important to think about what actually goes on within your company’s processes. Consider the following questions for each process:

• Is the emission a single stream or a complex mixture?
• Is the process operating on a batch or continuous basis?
• Is the sampling port in a designated and intrinsically safe area? If not, then equipment that potentially produces sparks or flames (e.g. FIDs) must not be used.
• Could particulate emissions cause problems?
•  Do emissions have a high moisture content? Moisture interferes with most sampling techniques, e.g. by saturating sorbent tubes and preventing uptake, and causing problems with laboratory equipment.
• Are the emissions at a high temperature? High stack temperatures will restrict the use of concentration and flow-measurement techniques, so it is wise to check the manufacturer’s specification before using equipment. In addition, high temperature emissions will affect sampling arrangements, due to the health and safety risks involved.

Your plant may have many different VOC streams, each of which could be monitored using a

variety of techniques. When selecting monitoring techniques and equipment it is important to

consider a number of factors, including:

• Type of data required and monitoring objectives, e.g. specific compounds or total carbon;

• Regularity of monitoring required, for example:

- Continuous, i.e. monitoring over an extended period to profile the emissions;

- Routine, i.e. regular monitoring for leaks as part of a maintenance programme;

- Periodic, e.g. monitoring to comply with legislative requirements, carried out, say, every six months;

• Safety considerations;

• Particular operating restrictions, e.g. process temperature, and humidity;

• Accuracy and repeatability required;

• Capital and operating costs.

The next step is to decide whether to:

• Contract out monitoring to a specialist company;
• Hire the equipment and perform the monitoring in-house;
• Purchase the equipment and carry out the monitoring in-house.

Estimating how much the monitoring programme will cost is an important step. Make sure you include the cost of any in-house resources, such as staff time.

When obtaining quotations from monitoring contractors, specify:

• What is to be monitored, how regularly and for how long;
• The specific information required and how it is to be reported;

Once you have all the cost information, you will be in a position to choose the most suitable

route for your monitoring programme.

When implementing monitoring you should:

• Assign responsibility for the programme to a member of staff;
• Set out what is to be measured, how and when, and draw up a proper monitoring programme including a timetable and key actions/responsibilities;
• Establish some means of recording the results (e.g. on a spreadsheet or database).

When monitoring is contracted out, make sure that your company and the contractor fully agree on the programme.

Regardless of the form of measurement used, it is important that all measurements are as accurate and representative as possible. You can achieve this by:

• Studying manufacturer or method notes carefully before making any measurements.
• Choosing duct access and measurement points carefully, bearing in mind that they should be located on the longest and straightest runs of ducting.
• Conducting monitoring over a period of several days of normal, steady production, and avoiding start-up and shutdown periods.
• Taking sufficient samples to provide statistically meaningful results. For example, a few sets of four or more readings (of adequate length) are usually sufficient to give a sensible overall mean. You should take into account process type and changes as these will influence the concentration gases and how this level changes with time.