Page 27 - igem-g-4 edition 2_Neat

IGEM/G/4 Edition 2
king post
Resting place for the centre of the crown framework within a watersealed gasholder tank.

laminar flow
Where all molecules of gas in a pipe travel more or less parallel to the walls of the pipe, across
the full area of a pipe, under flow conditions.

landfill gas
Mixture of gases produced as a result of microbial activity whenever biodegradable material is
deposited in a landfill site.

lateral
Horizontal pipe, connected to a riser, that conveys gas along one floor level within a building.

launch frame
Metal frame used to hold and guide an impact mole to achieve required direction.

launch pit
Excavation from which an impact making tool is launched.

leak test
Testing of an assembly of elements that have been previously subjected to, and passed,
tightness testing, intended to prove that the joints have been made properly and are free from
leaks.

leak tightness proving system
A means of proving that a safety shut-off valve (SSOV) system is not leaking by the
application of a pressure or vacuum between the SSOVs.

leakage survey
Systematic search for escapes of gas.

legacy gas supply arrangements
Gas supply arrangements (usually that have been installed prior to the publication of
IGEM/G/1) and that are not consistent with the installations defined as being “recommended
gas supply arrangements.”

legacy meter owner
Gas transporter (GT) which provided a meter under licence conditions prior to the publication
of IGEM/G/1 in a configuration not consistent with “recommended gas supply arrangements”.

lift
Telescopic section of a watersealed gasholder.

lighting torch
Hand-held burner ignited outside a combustion chamber.

light steel frame
Frame structures constructed from cold-rolled galvanised steel.

limit state
State of an installation when it no longer satisfies a particular design requirement.

linepack
Storage obtainable from diurnal pressure cycling of pipelines whose capacities are not fully
committed to transmission.

live gas working
Practice of carrying out work on, or associated with, a gas supply pipe while a release of gas is
taking place.

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