An ASTM Smoke Pump, or 'spot pump', is an instrument for evaluating the dark particle concentration of a

smoke Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product ...

. It is very widely used (2014) by heating engineers to assess

emissions Emission may refer to: Chemical products * Emission of air pollutants, notably: **Flue gas, gas exiting to the atmosphere via a flue ** Exhaust gas, flue gas generated by fuel combustion ** Emission of greenhouse gases, which absorb and emit rad ...

, most commonly from

fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but ...

-burning appliances such as a

wood stove A wood-burning stove (or wood burner or log burner in the UK) is a heating or cooking appliance capable of burning wood fuel and wood-derived biomass fuel, such as sawdust bricks. Generally the appliance consists of a solid metal (usually cast i ...

s or oil

boiler A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central h ...

s. It consists of a cylinder of precise size down which a close-fitting piston is pulled, sucking a sample of the smoke through a small nozzle against a filter paper (equivalent to Whatman No2 paper) so that a 'spot' is formed on the paper, the darkness of which can be compared with a standard chart to indicate the concentration of smoke. Measurements made using the ASTM Smoke Pump form part of statutory requirements in the USA and Germany. Unlike other smoke measurement methods, the ASTM Pump provides a permanent record and sample of the smoke. Because its use takes only a few seconds, it can provide a series of smoke samples over time, allowing boilers etc. to be evaluated over a complete burning cycle and graphic data to be collected. Because the system depends on ''comparison'' rather than an evaluation of the spot colour density, and because many successive samples can be taken, it is considered highly reliable. The ASTM Standard reports that, "The difference between test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed one-half of a smoke spot number for only one case in twenty."

Standard

The device is defined by the American Society for Testing and Materials (

ASTM ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, an ...

) in their Standard D2156 "Standard Test Method for Smoke Density in Flue Gases", first published in 1965, revised several times, most recently in 2018.

Calibration

The instrument provides the technician with a dark spot on a filter paper strip which is then compared with a standard darkness chart, commonly numbered 0 to 10, 0 being entirely white and 10 being entirely black. The darkness can be related to the likely concentration of dark smoke particles in the

flue gas Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produced a ...

by an empirical non-linear formula based on the OECD Document 'Methods of Measuring Air Pollution'. Where:
Sd = Actual smoke density on paper, in microgrammes (mcg) per square cm.
Ob = The observed paper obscuration, as a proportion (i.e. 0=white, 0.5=50% black, 1.0=black

References

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External links

Current D2156 Standard, at ASTMComplete D2156 Standard at Archive.orgTesto - a manufacturer of ASTM Smoke PumpsDwyer - a manufacturer of ASTM Smoke Pumps
Pollution control technologies Measuring instruments