What is the Difference: Instrument Data Sheets and Application Data Sheets

An Application Data Sheet may seem redundant when you already have a completed Instrument Data Sheet from the buyer/user yet there are differences in the kinds of information provided by each that will help assure the best possible instrument selection. Because today’s equipment is complex, it is very easy for manufactures to imply, and customers to infer, for example that a function or a feature is standard when it actually requires an upgrade or is not even available or suitable for the specific application being addressed.
An Instrument Data Sheet (IDS) is a document containing specification and information of an instrument device. It specifies general information of instrument such as tag number identification, service description, location (line number/equipment number), P&ID number or drawing number reference, process data (if applicable), calibrated range (if applicable), material, performance details (such as accuracy, linearity – if applicable), hazardous certification (for electrical device), accessories required, etc. The details of information in data sheet may differ among each types of instrument such as transmitter, switch, gauge, control valves, etc. The Instrument Data Sheet is typically completed and supplied by the user or purchaser.

The Application Data Sheet (ADS) is typically specific to the manufacturers proposal. It allows a manufacture to qualify which technology best fits the application described and what available options will facilitate the performance requested on the IDS. The ADS is also a useful tool for technical review of the sales proposal by the buyer/user so that they can better understand exactly what is being offered.

The user often has the challenge of making a decision between two or more offers that may or may not be equals. Sometimes there is inconsistent nomenclature describing similar, if not identical, instrument features. Different units maybe used to express the same specifications and different test conditions often are used by manufacturers to create specifications that favor their equipment.

For example, the terms digital flow control, electronic flow control, and programmable pneumatic control all appear in discussions on GC carrier gas flow control. Manufacturers are obviously trying to differentiate their offerings, but it places a burden on the user to determine the exact function being specified. Other discrepancies occur because of a lack of precision in language. For example; Linearity, linear dynamic range, and dynamic range are used as the technical names for the same detector property.

A completed Application Data Sheet based on the information contained on the Instrument Data Sheet will help ensure that the equipment selected is a “best fit” for the application so that performance and reliability meets expectations.



Flare systems are designed to safely burn excess hydrocarbon gases that cannot be recovered or recycled. Flare stacks are primarily used for burning off flammable gas released by pressure relief valves during unplanned over-pressuring of plant equipment. During flaring, the excess gases are combined with steam and safely burned in the flare. This is safer and more environmentally friendly than releasing the hydrocarbons directly into the atmosphere.


During normal operations, hydrocarbons are refined, collected and routed for further processing into products such as gasoline. When a facility experiences a process interruption, such as an unplanned loss of power, the system may be unable to send the hydrocarbons through for further refining. Flares are also used to ensure safety during the startup and shutdown of equipment when gases generated by those processes cannot be safely recycled into the refinery.

In both cases, the excess hydrocarbons are routed to the flare system where they are combined with steam and safely burned. Combining the excess hydrocarbons with steam ensures maximum combustion so that chemical destruction is complete and  emissions are minimized.

Improperly operated flares may emit methane and other volatile organic compounds as well as sulfur dioxide and other sulfur compounds, which are known to exacerbate asthma and other respiratory problems. Other emissions from improperly operated flares may include, aromatic hydrocarbons (benzene, toluene, xylenes) and benzapyrene, which are known to be carcinogenic.


Similar to the pilot light on a household gas stove or hot water heater, a small flame at the top of the flare burns continuously, ensuring the system is ready for immediate use. Depending upon the construction of the flare, weather conditions, and ambient lighting, the pilot flame may or may not be visible from the ground. When flaring occurs, the flame and noise level will increase due to the increased volume and pressure of the gases being burned by the flare. Refinery operators continuously monitor the flare system to minimize noise and smoke levels, while still burning the gases cleanly and safely.

You can learn more about the important role flares play in the daily operational safety of refineries and their communities with this refinery flare fact sheet.