[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-662888-105":59,"doc-detail-662888-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","general-notes-drainage-installation-requirements","GENERAL NOTES - Drainage Installation - Requirements","","Drainage installation general notes specifying compliance, unit conventions, and detailed pipework requirements for Hong Kong building works. Includes rules for waste, soil, and vent piping connections, trap water seal and anti-siphon ventilation, horizontal vent fall continuity, and required gradients for various pipe diameters. Covers underground pipe bedding and concrete surround, inspection panels, manhole invert level references, testing prior to backfill, access for cleaning rods, protection and fire/exit-stair enclosure requirements, and stormwater discharge elevations, with additional guidance on joint inspection and as-built record submission.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":40,"@type":76,"position":81},"https://docshare.wps.com/document/research-report/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/general-notes-drainage-installation-requirements/662888/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/general-notes-drainage-installation-requirements/662888.png","ImageObject",300,407,{"name":92,"@type":93},"LangkahRina","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-30","2026-10-28",true,{"@type":102,"interactionType":103,"userInteractionCount":29},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What regulations and unit standards must the drainage installation follow?","Question",{"text":112,"@type":113},"The installation must comply with Hong Kong Buildings Ordinance and Building Regulations, and current Environmental Protection Department regulations. All dimensions and pipe sizes shown are in mm unless stated otherwise.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How should traps and anti-siphon ventilation be arranged for waste pipe connections?",{"text":117,"@type":113},"Where a waste pipe connects to a soil pipe, each fitment trap must have a water seal not less than 80mm and be vented using an anti-siphonage pipe or an anti-siphonage trap.",{"name":119,"@type":110,"acceptedAnswer":120},"What are the requirements for underground drainage construction and verification before backfilling?",{"text":121,"@type":113},"Underground pipes must be laid on a concrete bed (not less than 100mm thick) and provided with surrounding concrete as specified. Underground drains must be duly tested and comply with stated requirements prior to backfilling of trenches, and joint inspection plus as-built records must be furnished.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},662888,1793223074,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":39,"category_name":40,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":29,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":44,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":129,"read_time":143},962090893776,"https://ap-avatar.wpscdn.com/davatar_155a257f0dc6eb9ab79c44ca47cae57d","| GENERAL NOTES\u003Cbr>1. THE WHOLE DRAINAGE INSTALLATION SHALL COMPLY WITH THE REQUIREMENTS OF THE BUILDINGS ORDINANCE AND BUILDING REGULATIONS AND THE CURRENT REGULATIONS OF HONG KONG ENVIRONMENTAL PROTECTION DEPARTMENT.\u003Cbr>2. ALL DIMENSIONS AND PIPE SIZES SHOWN ON THE DRAWINGS ARE IN mm UNLESS OTHERWISE STATED.\u003Cbr>3. WHERE THE WASTE PIPE FROM A WASTE FITMENT IS CONNECTED TOA SOIL PIPE, THE TRAP PROVIDED FOR EACH FITMENT SHALL HAVE A WATER SEAL NOT LESS THAN 80mm AND BE VENTED BY MEANS OF ANTISYPHONAGE PIPE OR ANTISYPHONAGE TRAP.\u003Cbr>4. HORIZONTAL VENT PIPE SHALL BE INSTALLED IN A MANNER THAT THERE IS A CONTINUOUS FALL BACK AT A GRADIENT OF NOT LESS THAN 1 IN 300 INTO THE DISCHARGE PIPE SYSTEM.\u003Cbr>5. UNLESS OTHERWISE STATED GRADIENT OF DRAIN PIPES SHALL BE AS FOLLOWS:-\u003Cbr>∅100 ∅150 ∅225\u003Cbr>∅300 OR ABOVE\u003Cbr>FALL 1 : 40\u003Cbr>FALL 1 : 70\u003Cbr>FALL 1 : 100\u003Cbr>FALL 1 : 150\u003Cbr>6. ALL UNDERGROUND PIPES SHALL BE PROVIDED WITH PIPE HAUNCHING OR SURROUNDED BY CONCRETE AS SHOWN ON DETAILS DRAWINGS. THE DRAINAGE SUB-CONTRACTOR SHALL CHECK THE SITE BEFORE CONSTRUCTION AND RECTIFY THE PROPOSED PIPE ROUTING.\u003Cbr>7. INSPECTION PANELS OF ADEQUATE SIZE SHALL BE PROVIDED AT PIPE DUCTS AND SHAFTS FOR INSPECTION AND MAINTENANCE OF PIPES.\u003Cbr>8. ALL BACK INLET TRAPPED GULLIES SHALL BE VENTILATED BY MEANS OF 80mm DIA. VENT PIPE.\u003Cbr>9. ALL SOIL WASTE AND VENT STACKS SHALL BE CARRIED UP TO THE ROOF AND TERMINATED AT NOT LESS THAN 1000mm ABOVE THE ROOF OR AS SHOWN IN DRAWINGS.\u003Cbr>10. EVERY ANTI-SYPHONAGE PIPE SHALL BE CONNECTED WITH BRANCH SOIL PIPE OR BRANCH WASTE PIPE AT A POINT NOT MORE THAN 300mm FROM TRAP OUTLET.\u003Cbr>11. WHETHER SHOWN ON THE DRAWINGS OR NOT, SUFFICIENT ACCESS SHALL BE PROVIDED BY MEANS OF CLEANING EYES OR OTHER APPROVED METHOD TO ENABLE ALL DRAINAGE PIPES TO BE CLEARED OF ANY OBSTRUCTION. SUCH ACCESS POINTS SHALL BE SO SITEDAT TO ALLOW CLEARANCE FOR THE EASY ENTRY OF CLEANING ROD.\u003Cbr>12. ALL BENDS IN SOIL PIPES AND WASTE PIPES SHALL HAVE AN OBTUSE ANGLE AND HAVE THE LARGEST PRACTICABLE RADIUS OF CURVATURE. THE BENDS SHALL NOT CHANGE IN ANY WAY OF THE SECTION OF THE PIPE ANDA CLEANING EYE SHALL BE PROVIDED AT OR NEAR THE BEND.\u003Cbr>13. ALL FLOOR DRAINS ARE TO BE COMPLETED WITH FLAT GRATING. THEIR SIZE ARE NOTED AS FOLLOW:\u003Cbr>OUTLET SIZE\u003Cbr>∅∅∅∅\u003Cbr>GRATING SIZE\u003Cbr>∅∅∅∅\u003Cbr>FOR REFERENCE ONLY\u003Cbr>\u003Cbr>14. THE SUB-CONTRACTOR SHOULD CHECK AND ALLOW ADEQUATE FALL FOR THE SOIL/WASTE PIPE RUNNING ON FLOOR LEVEL.\u003Cbr>15. ALL PIPES PASSING THROUGH EXIT STAIRCASES, FIRE PROTECTED LOBBIES SHALL BEENCLOSED IN FRR-/60/60 MATERIAL & BASEMENT IN FRR-/120/120 MATERIAL BY MAIN CONTRACTOR.\u003Cbr>16. EXPANSION JOINTS SHALL BE PROVIDED FOR PIPEWORK PASSING THROUGH BUILDING EXPANSION JOINTS.\u003Cbr>17. UNLESS OTHERWISE STATED, BRANCH PIPE SIZE SHALL BE AS FOLLOWS:\u003Cbr>WASTE BRANCH FOR EACH WASH BASIN WASTE BRANCH FOR EACH KITCHEN SINK\u003Cbr>WASTE BRANCH FOR EACH FLOOR DRAIN IN TOILET\u003Cbr>WASTE BRANCH FOR EACH SHOWER DRAIN IN TOILET WASTE BRANCH FOR EACH BATH IN TOILET\u003Cbr>WASTE BRANCH FOR EACH FLOOR DRAIN IN PLANT RM. SOIL BRANCH FOR EACH URINAL\u003Cbr>SOIL BRANCH FOR EACH WATER CLOSET VENT BRANCH FOR EACH WATER CLOSET VENT BRANCH FOR EACH URINAL\u003Cbr>32mm 40mm 50mm 50mm 40mm 100mm 40mm 100mm 50mm 32mm\u003Cbr>18. ALL MANHOLE AND BITG FRAMES AND COVERS (INCLUDING CAST IRON COVER AND MATCHING COVER) SHALL BE OF AN APPROVED DESIGN CONFORMING TO THE FOLLOWING REQUIREMENTS, UNLESS OTHERWISE INDICATED:\u003Cbr>a. INDOOR CARPARK AREA/DRIVE WAY-HEAVY DUTY TYPE DOUBLE SEAL\u003Cbr>b. OUTDOOR CARPARK AREA/DRIVE WAY-HEAVY DUTY TYPE SINGLE SEAL\u003Cbr>c. INSIDE BUILDING-MEDIUM DUTY TYPE DOUBLE SEAL\u003Cbr>19. ALL UNDERGROUND DRAINS ARE TO BE LAID ON A CONCRETE BED NOT LESS THAN 100mm THICK AND AT LEAST 150mm WIDER THAN THE PIPE BORE AND AUNCHED UP BOTH SIDES WITH CONCRETE TO MEET THE PIPE BARREL TANGENTIALLY.\u003Cbr>20. ALL INVERT LEVELS SHOWN ON MANHOLES ARE THE INVERT LEVEL OF THE MAIN CHANNELS IN THE CENTRE OF MANHOLES.\u003Cbr>21. ALL UNDERGROUND DRAINS SHALL BE DULY TESTED AND COMPLIED WITH THE\u003Cbr>REQUIREMENT STATED ON PNRC","cbCaiuuGJpSakIWv","https://ap.wps.com/l/cbCaiuuGJpSakIWv","pdf",2752296,"English","# General Notes\n## Compliance and Units\n## Pipe Connections, Traps, and Venting\n## Gradients, Bedding, and Underground Works\n## Inspection, Testing, and Access\n## Protection, Enclosures, and Records","[{\"question\":\"What regulations and unit standards must the drainage installation follow?\",\"answer\":\"The installation must comply with Hong Kong Buildings Ordinance and Building Regulations, and current Environmental Protection Department regulations. All dimensions and pipe sizes shown are in mm unless stated otherwise.\"},{\"question\":\"How should traps and anti-siphon ventilation be arranged for waste pipe connections?\",\"answer\":\"Where a waste pipe connects to a soil pipe, each fitment trap must have a water seal not less than 80mm and be vented using an anti-siphonage pipe or an anti-siphonage trap.\"},{\"question\":\"What are the requirements for underground drainage construction and verification before backfilling?\",\"answer\":\"Underground pipes must be laid on a concrete bed (not less than 100mm thick) and provided with surrounding concrete as specified. Underground drains must be duly tested and comply with stated requirements prior to backfilling of trenches, and joint inspection plus as-built records must be furnished.\"}]","GENERAL NOTES - Drainage Installation - Requirements | PDF",23]