Coalbed methane can cause explosion when transported in pipelines. Installing metal foam in the transportation pipeline can suppress coalbed methane explosion. But it is uncertain of the relationship between explosion suppression effect and the distance from the ignition end to the metal foam. Explosion tests were conducted in the empty pipe and in the pipe containing copper foam at 400, 900, and 1200 mm from the ignition end when the initial pressures of 6, 7, 8, 9 and 10 kPa. Copper foam provided better inhibition effect when it was close to the ignition end at initial pressures of 6, 7, and 8 kPa. When the initial pressure was 10 kPa, copper foam had an inhibition on explosion overpressure but an incentive on explosion flame velocity. When the initial pressure was 9 kPa, the effect of metal foam on explosion suppression was closely related to the position of the metal foam. (C) 2019 Elsevier B.V. All rights reserved.