A method of installing an Emergency Flow Restrictor Device (EFRD) on a pipeline without stopping the flow of fluid through the pipeline includes the steps of: assembling first and second face plates on a pipeline such that the first and second sealing face are in face to face, spaced relation; assembling a cutting device between the first face plate and the second face plate; assembling a valve body that has an access opening on a length of pipeline such that the valve body encloses the first and second face plates and the cutting device; installing an access valve on the access opening; operating the cutting device to sever the pipeline between the first and second sealing faces; retracting the cutting device and severed section of pipeline; and attaching a valve gate member of the EFRD to the access opening.