How many pump strokes does a Draeger tube take, and how long does a reading take?
The number of strokes is set per tube and per scale and is printed on the tube next to that scale; it ranges from 1 stroke (Ammonia 5/a, high range) to 100 strokes (Formaldehyde 0.2/a with the activation tube). One stroke of the Draeger accuro or X-act 5000 draws 100 mL (± 5 %), so the strokes define the air volume the scale was calibrated for, and the defined measuring range applies only with a Draeger pump (handbook pp. 30, 33, 114). The measuring time is the average time for that range: the handbook gives 10 seconds to 15 minutes as the span for short-term tubes, and every tube entry states its own, for example approx. 1.5 min for Formaldehyde 0.2/a at 10 strokes and approx. 3 min at 20 strokes (pp. 35, 181).
Draeger accuro detector tube hand pumpBellows pump, 100 mL (± 5 %) per stroke, 1 to 50 strokes and higher, no power supply (handbook p. 31)Why a fixed number of strokes? The handbook describes the tube and pump as a single measuring system: each type of tube is calibrated in batches together with a Draeger pump, and the scale assumes exactly the volume those strokes draw. Draeger and the pump standards therefore require a tube to be used with the matching pump from the same manufacturer; using other pumps with Draeger tubes, or other tubes with Draeger pumps, can impair the function of the measurement system (pp. 28–29). On the accuro the end of a stroke is shown by a pressure-controlled end-of-stroke indicator in the pump head; on the X-act 5000 the stroke count is entered and the pump runs it automatically, 1 to 199 strokes (pp. 30, 33).
Strokes, volume and time, by the handbook
Examples from the handbook entries (strokes / measuring time)
- Ammonia 5/a (CH20501): 10 strokes / approx. 60 s on the 5 to 70 ppm scale; 1 stroke / approx. 10 s on the 50 to 700 ppm scale.
- Formaldehyde 0.2/a (6733081): 10 strokes / approx. 1.5 min for 0.5 to 5 ppm; 20 strokes / approx. 3 min for 0.2 to 2.5 ppm (p. 181).
- Formaldehyde 2/a (8101751): 5 strokes / approx. 30 s for 2 to 40 ppm (p. 182).
- Acetaldehyde 100/a (6726665): 20 strokes for 100 to 1000 ppm.
- Every tube page on this site prints its own strokes and measuring time from the handbook entry, under "specifications".
Tubes with low, middle and high stroke counts
6 items · prices liveStrokes and times from the handbook entries; the tube page has the full entry. Orders ship in 1–2 business days.
Every Draeger tube we list, with the handbook data, is on the Draeger tubes A–Z chart; each gas has its own page with the OSHA and NIOSH limits.
Questions people ask
How many strokes does a Draeger tube need?
The number printed on the tube next to its scale; the handbook entry for every tube states it. Our tube pages show it under specifications.
How much air is one stroke?
100 mL (± 5 %) on the accuro and the X-act 5000 (handbook pp. 30, 33).
Can I use fewer strokes to save time?
The defined measuring range applies only with the stated strokes on a Draeger pump (p. 114). Where Draeger allows a different count, the entry states the extended range and the factor to apply.
How long does a Draeger tube reading take?
Between 10 s and 15 min for short-term tubes; each entry states the average time for its range (p. 35).
Why does Draeger say to use only a Draeger pump?
Because tube and pump are calibrated together as one system; the handbook states that mixing makers can impair the measurement (pp. 28–29).
Related guides
The Draeger accuro pump: how it works, the leak check, strokes and the kitsaccuro pumpHow to read a Draeger tube: the stain, the scale and the three cases the handbook describesReading a tubeDraeger X-act 5000 and X-act 7000: two different instruments, and what each one readsX-act 5000 and X-act 7000What do Draeger tube names mean? 0.2/a, 5/b, 100/a-P, 20/a-D and the part numberTube names and codesStandards and ratings on this page are as published in the documents named and by the manufacturers named. The employer’s hazard assessment and written program decide what applies at a given workplace. Verify a rating on the product and its spec sheet before use.