sentences:  The sample is ignited on one end and time is measured until the flame front gets to the other end.Burn rate (typically expressed in 'mm/s' or 'in/s') is the sample length over time at a given pressure and temperature.For solid fuel propellant, the most common method of measuring burn rate is the Crawford Type Strand Burning Rate Bomb System (also known as the Crawford Burner or Strand Burner), as described in MIL-STD-286C.