Drainage

23 articles

• Back Inlet Gully vs Hopper Head: Where Each is Used
  Back inlet gully vs hopper: BIG traps waste (P/S-trap) at low-level ground floor for washing machine/sink/bath outlets; hopper head is open funnel for rainwater/overflow at first floor+; H approved doc regs, BS EN 12056-2 gravity drainage
• Below-Ground Drainage: Pipe Bedding, Gradient and Cover
  Below-ground drain laying: Class N/B/S bedding per BS EN 1610, gradient 1:40-1:80 (100mm), 1:60-1:150 (150mm), 0.75 m/s velocity, cover 600/900/1200mm garden/drive/road; Approved Document H1, CDM 2015 trench safety
• Blocked Drains UK: Rodding, Jetting & When to Call Help
  Blocked drain diagnosis: rodding, high-pressure jetting, CCTV survey, root intrusion; responsibility boundaries
• Drain CCTV Survey: MSCC4 Defect Codes & Report Guide UK
  MSCC4 defect grading A/B/C codes, survey reporting format, when to commission (purchase, blockage, subsidence), report interpretation for repair decisions
• Drain Rodding vs High-Pressure Jetting: When to Use Each
  Rodding = first-line, local blockage within ~10m, doesn't clean bore; jetting clears grease/roots/scale over long runs but can damage weak pipe; jet then CCTV survey recurring blockages; BS EN 752/12056, Part H, Confined Spaces Regs 1997, PUWER
• Drainage Near Trees: BRE Digest 298 Safe Distances Guide
  BRE Digest 298 species/height safe distances, shrinkable clay (NHBC Chapter 4.2) risk zones, flexible joints every 600mm, Building Control notification requirements
• Foul Drainage Design: Stack Sizing & Approved Document H
  Above-ground stack sizing using discharge unit method, branch gradient 18–90mm, ventilation via primary stack or AAV, Approved Document H table requirements
• Gully Types and Installation: Back-Inlet, Trapped and Yard Gullies
  Gully connects surface/waste water to underground drainage with a trap seal; trapped, back-inlet (BIG) and yard gullies; foul vs surface water; Part H, BS EN 752/12056, BS EN 1433 (channels), BS EN 124 (gully/manhole tops)
• Inspection Chamber & Manhole Depths: Building Regs Guide
  Inspection chambers and manholes: precast concrete, plastic chambers, cover grades, benching requirements, Part H compliance
• Manhole Cover Types and Loading Classes
  Manhole covers BS EN 124-1:2015: A15 (1.5t pedestrian), B125 (12.5t footways/parking), C250 (25t kerb 500mm zone), D400 (40t carriageway), E600 (60t HGV docks), F900 (90t airports); ductile iron vs composite, single vs double seal
• No-Dig Drain Repair Methods: CIPP, Patch Lining & Resin
  Patch lining for local defects, CIPP full relining for long runs, resin injection for joint repair, lateral relining — access, cost, and material selection
• Petrol & Oil Interceptors: BS EN 858 Class I/II Guide UK
  BS EN 858 Class I (≤5mg/l) vs Class II (≤100mg/l) selection, bypass volume calculation, 6-monthly maintenance, EA discharge consent requirements
• Rainwater Goods Sizing: Gutters and Downpipes
  Rainwater goods UK: BS EN 12056-3:2000 design rainfall 75mm/hr cat 2 / 150mm/hr cat 3 hospitals; 112mm half-round drains 60m2 with one 68mm RWP, 150mm deep-flow for 100m2+ / single-storey extensions
• Rainwater Harvesting: BS 8515 Tank Sizing & UK Regulations
  Rainwater harvesting: non-potable use, tank sizing (CIRIA C539), first-flush diverters, Water Regulations backflow prevention
• Root Intrusion in Drains: CCTV Survey & Removal Guide
  High-risk species (willows, poplars, ash), CCTV identification codes, high-pressure jetting (40 bar) vs mechanical root cutting vs relining as permanent fix
• Septic Tank Rules 2020: General Binding Rules & BS EN 12566
  Septic tanks and cesspools: 2020 General Binding Rules, direct watercourse discharge now non-compliant, BS EN 12566, drainage field design and percolation testing, EA registration
• Soakaway Design & Installation: BRE Digest 365 Calculations
  Soakaway design: BRE Digest 365 percolation test method, crate vs rubble fill, minimum 5m from buildings
• Soakaway Sizing Calculator: BRE Digest 365 & Part H Guide
  BRE Digest 365 percolation testing (3 pits × 3 tests), infiltration rate f calculation, S = (A_d × i × D) - (a_s × f × D) sizing equation, worked example for 75m² roof on sandy clay, 5m min from building, 2.5m from boundary, 24h drain target, granular vs crate construction
• SuDS Design for Small Sites: CIRIA C753 Guide UK
  SuDS design for small sites: CIRIA C753, greenfield runoff rates, BRE 365 infiltration testing, attenuation volume calculation, SAB approval process in Wales
• SuDS Drainage Systems: Part H Hierarchy & Design Guide UK
• Underground Drainage: Pipe Sizes, Gradients & Part H UK
  Underground drainage: 100mm/150mm pipe sizes, 1:40 gradient for 100mm, Approved Document H requirements, inspection access
• When Is a Grease Trap Required and How Do They Work?
  FOG requirement for commercial kitchens, BS EN 1825 sizing, Part H, trade effluent consent, passive vs AGRU (automatic grease removal unit) comparison
• When Is a Sewage Pumping Station Required? Sizing Guide
  When pumped drainage is needed, BS EN 12050 standards, wet well sizing, Sewers for Adoption 7th Edition, Section 104 adoption, alarm requirements