Peak Flow Meter

Quick Answer: A peak flow meter is a handheld tube with a sliding marker that measures peak expiratory flow, the fastest rate at which air can be blown out of the lungs, in litres per minute. In teaching it is used in human physiology and nursing practicals on lung function.

How a Peak Flow Meter Works

Inside most mechanical meters of this kind, a blast of air pushes a spring-loaded piston or vane along the body of the tube. The piston drives a small marker along a scale, and the marker stays at the furthest point reached, so the reading can be taken after the blow is over. The scale reads in litres per minute because the meter records the highest rate of flow, not the volume of air.

That is the key difference from a lung volume bag or a spirometer volume trace. A student with large lungs but a slow, weak blow can record a modest peak flow, while a short, sharp blow gives a high one. Peak flow depends mainly on the calibre of the large airways and the effort of the expiratory muscles, which is why it falls when the airways narrow.

The listing does not give the scale range or the construction of the meter. Meters are made in standard ranges for adults and low ranges for children, so state the age group of the users when ordering. LabEquip lists this meter for teaching and demonstration and does not claim medical-device registration for diagnosis or home monitoring.

Care & Handling

• Fit a new disposable mouthpiece, or a cleaned personal one, for each student.
• Clean the meter as its instructions describe; many can be washed in warm soapy water but must then air-dry fully before use.
• Do not blow into the meter with food or drink in the mouth, since debris can make the piston stick.
• Slide the marker back to the bottom of the scale before every blow.

Specifications

Applications

• Human physiology practicals on lung function in school, college and nursing courses
• Class investigations comparing measured peak flow with height, age and sex
• Showing how posture and effort change the result of a forced breath
• Teaching nursing students the technique they will later coach patients to use

Why Choose LabEquip

Peak flow meters are ordered by schools, nursing colleges and physiology departments that want a quick lung-function measurement for every student. LabEquip supplies them with lung volume bags in its Biology Lab Products range; class orders can be discussed on the contact page.

Frequently Asked Questions

What is the correct technique for a peak flow reading?

Stand up, reset the marker, take the deepest breath possible, seal the lips around the mouthpiece and blow out as hard and fast as possible in one short blast. Repeat three times and record the highest reading.

How is a peak flow meter different from a spirometer?

It records only the highest flow rate of one forced breath. A spirometer measures volumes and flow over the whole breath, including the forced expiratory volume in one second and the forced vital capacity.

Why is the highest of three readings used?

Peak flow depends heavily on effort and technique, and early blows are often lower while the student learns the movement. The highest of three is the most representative of true peak flow.

What affects a person’s peak flow?

Height, age and sex have the largest effect, together with effort. Narrowed airways, as in asthma, reduce peak flow, which is why doctors use the meter to follow that condition.

Can this meter be used for asthma monitoring at home?

This listing is supplied for teaching and demonstration. Anyone monitoring a medical condition should use the meter and action plan recommended by their doctor.

Can one meter be shared by a whole class?

Yes, provided every student uses a separate disposable mouthpiece or one that has been cleaned. Clean the meter itself after the practical as its instructions advise.

Last Updated: September 2026