This is the fourth edition of CSA B108, Natural gas refuelling stations installation code. It supersedes the previous editions published in 2014, 1999, and 1995, under the title Compressed natural gas fueling stations installation code. This Code consists of the following: a) Part 1 - Compressed natural gas refuelling stations installation code; and b) Part 2 - Liquefied natural gas refuelling stations installation code. Part 1 is applicable to compressed natural gas (CNG) refueling stations. Part 2 is applicable to liquefied natural gas (LNG) refueling stations, including LNG to CNG conversion systems. Part 2 supersedes Annex D of CSA Z276, LNG vehicle fuelling stations. Significant changes in this edition include the following: a) Added a new Part 2 to address the design, location, construction, operation, operator training, and maintenance of LNG refueling stations, including mobile refuelling units, with single containment storage tanks up to 265 m3 (70 000 gal) water capacity employed for vehicle LNG dispensing operations. b) Reorganized content for consistency of organization between Parts 1 and 2. c) Revised scope, definitions, and requirements to include distinction between residential fuelling appliances (RFAs) and listed non-residential vehicle fuelling appliances (VFAs) d) Revised Table 2 of Part 1, Electrical classification of space surrounding gas storage facilities, to indicate plugged ends of containers are not considered openings. e) Clarified distinction between and requirements for "fill post" and "dispensers" at public and private refuelling locations. f) Clarified requirements for hose length and prevention from contact with ground. g) Clarified requirements for location of ESD button. h) Added Figure 5 of Part 2 for hazardous area zones around CNG relief valve stack for clarification of requirements. i) Clarified requirements for exits from a refuelling room. j) Clarified refuelling area ventilation requirements. k) Editorial revisions to clarify wording and references, resolve conflicts identified with other documents, provide consistency and clarification between Part 1 and Part 2, correct metrication values, and harmonize definitions with other industry codes and standards. This Code has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group.