HVDH Domestic heating design guide (2021)

The PDF version of the Domestic heating design guide has been corrected to reflect corrections to Table 3.18.

THE Domestic heating design guide has been produced to assist specifiers and designers of ‘wet’ central heating systems for single-family and multiple-occupancy buildings and covers both new and existing dwellings. Wet central heating systems are low-pressure hot water (LPHW) systems for distributing heat throughout a building; they are sometimes called ‘hydronic’ systems. The Guide is also intended for practitioners who want to gain a better understanding of the principles and methods underlying the design process, and it offers a method for reaching agreement with a client as to what is needed and will be provided.

This Guide covers the most widely used system designs, but contains sufficient information to inform a more general design process when the standard approach is not suitable.

The Guide is intended:

• To be used in conjunction with other publications. Reference must always be made to relevant building and other regulations and standards. Associated statutory guidance should also be consulted. All references to legislation, guidance and standards are only correct at the time of publication.

• To aid in the design and specification of LPHW space- and water-heating systems connected to an automatically controlled heat source. This includes open-vented and unvented/sealed heating and domestic hot water heating systems.

• For use in The British Isles.

This Guide is not intended to cover:

• The design and regulatory requirements for the heat generators themselves. Specific requirements for the installation of gas, solid fuel, wood or biomass, liquid fuel-fired and electrical heating equipment, including fuel storage where applicable, are provided in other publications. Only outline details and the implications of the LPHW system for the heat source are given in this Guide (see section 1.6).

• The design of hot and cold water system draw-off pipework or sanitary appliances.

• Installation work.

Contents of the 2021 edition:

0 Introduction

• 0.1 Contents
• 0.2 Version Control
• 0.3 DBSP Committee Member Organisations
• 0.4 Foreword
  • 0.4.1 Brexit
• 0.5 Domestic Heating Design Guide Introduction
  • 0.5.1 Objective
  • 0.5.2 Scope
  • 0.5.3 How to Use this Guide

1 System Information

• 1.1 Contents
• 1.2 Version Control
• 1.3 Relevant Regulations, Standards and Documents
• 1.4 Introduction
• 1.5 Energy Efficiency and Carbon Emissions
  • 1.5.1 What Energy Efficiency Means
  • 1.5.2 Environmental Impact
  • 1.5.3 Primary and Delivered Energy
  • 1.5.4 Why Energy Efficiency is Important
  • 1.5.5 Home Energy Ratings and Energy Performance Certificates
  • 1.5.6 Heat Generator Efficiency
  • 1.5.7 Hot Water Storage Efficiency
  • 1.5.8 Controls
• 1.6 Heat Generator Considerations
  • 1.6.1 Heat Generator Efficiency and Performance Standards
  • 1.6.2 Gas Boilers
  • 1.6.3 Liquid Fuel Boilers
  • 1.6.4 Biomass Fuel
  • 1.6.5 Heat Pumps
  • 1.6.6 Electric Heating
  • 1.6.7 Solar Heating
  • 1.6.8 Heat Networks and Heat Interface Units
• 1.7 Ventilation
  • 1.7.1 Ventilation in Living Space
  • 1.7.2 Combustion Air and Safe Operation of Flues

2 Customer Liaison

• 2.1 Contents
• 2.2 Version Control
• 2.3 Introduction
• 2.4 Pre-Installation Documentation
  • 2.4.1 The Specification
  • 2.4.2 The Quotation
• 2.5 Post-installation Documentation
  • 2.5.1 Commissioning
  • 2.5.2 Handover
  • 2.5.3 Maintenance
• 2.6 Appendix
  • 2.6.1 Sample Survey Checklist – Blank
  • 2.6.2 Sample Quotation Sheet – Blank

3 System Design (Heat Loss)

• 3.1 Contents
• 3.2 Version Control
• 3.3 System Design (Heat Loss) – Introduction
• 3.4 Heat Loss Calculation – Principles
  • 3.4.1 Ventilation and Natural Infiltration Heat Loss
  • 3.4.2 Calculation of Fabric Heat Loss
• 3.5 Heat Loss Calculation – Considerations
  • 3.5.1 Surface Area of a Building
  • 3.5.2 U-values
  • 3.5.3 Design Temperatures
  • 3.5.4 Ventilation
• 3.6 Annual Energy Estimation
• 3.7 Heat Loss Procedures
• 3.8 System Design (Heat Loss) – Appendix
  • 3.8.1 Thermal Conductivity Table
  • 3.8.2 U-value Tables
  • 3.8.3 Worksheet A – Heat Losses – Blank
  • 3.8.4 Worksheet A – Heat Losses – Instructions

4 System Design (Domestic Hot Water)

• 4.1 Contents
• 4.2 Version Control
• 4.3 System Design (Domestic Hot Water) – Introduction
• 4.4 Hot Water Sources
  • 4.4.1 Hot Water Storage Cylinders
  • 4.4.2 Combination Boilers
  • 4.4.3 Thermal Stores
• 4.5 Other Hot Water Considerations
  • 4.5.1 Bacteria (Legionella) Protection
  • 4.5.2 Scalding Prevention
  • 4.5.3 Secondary Circulation
  • 4.5.4 Hard Water
  • 4.5.5 Hot Water Supply Pipework
  • 4.5.6 Wastewater Heat Recovery

5 System Design (Heating)

• 5.1 Contents
• 5.2 Version Control
• 5.3 Introduction
• 5.4 System Layout
  • 5.4.1 Typical System Layout
  • 5.4.2 Y-Plan Configuration
  • 5.4.3 Primary Circuit Radiator
  • 5.4.4 Open-Vented Systems
  • 5.4.5 One-Pipe Circuits
  • 5.4.6 Reverse-Return Layout
  • 5.4.7 Reverse Circulation
• 5.5 Heat Emitters
  • 5.5.1 General
  • 5.5.2 Heating System Water Temperature
  • 5.5.3 Exposed Pipework Emissions
  • 5.5.4 Output Emission Factors
  • 5.5.5 Radiator Selection
  • 5.5.6 Underfloor Heating
• 5.6 Pipework
  • 5.6.1 Pipework Sizing Strategy
  • 5.6.2 Pipework Sizing Strategy – Approximation
  • 5.6.3 Pipe Sizing Design: Fluid Velocity
  • 5.6.4 Pipe Sizing Design: Frictional Resistance
• 5.7 Sizing the Heat Source
  • 5.7.1 Heat Generator/Boiler Sizing Method
• 5.8 Circulators
  • 5.8.1 Circulator Selection
  • 5.8.2 Circulator Position
  • 5.8.3 Circulator Sizing
  • 5.8.4 Isolating Valves
  • 5.8.5 Integral Circulators
  • 5.8.6 Circulator Fault Diagnosis
• 5.9 Fluid Expansion Compensation
  • 5.9.1 Sealed Heating Systems
  • 5.9.2 Open-Vented Systems
• 5.10 Low-Loss Headers and Manifolds
  • 5.10.1 Low-Loss Headers
  • 5.10.2 Manifolds
• 5.11 System Controls
  • 5.11.1 Introduction
  • 5.11.2 Control functions – Inputs
  • 5.11.3 Control functions – Outputs
  • 5.11.4 Control Functions – Controller
  • 5.11.5 Zoned Heating
  • 5.11.6 Recommended Control Systems
• 5.12 Pipework Insulation
  • 5.12.1 Insulation of Heating System Pipework
  • 5.12.2 Insulation of Domestic Hot Water Pipework
  • 5.12.3 Insulation in Unheated Areas
  • 5.12.4 Insulation of Condensate Pipework
  • 5.12.5 Installation of Insulation
• 5.13 Water Treatment
  • 5.13.1 Debris, Corrosion and Limescale
  • 5.13.2 Antifreeze
  • 5.13.3 Microbiological Contamination
• 5.14 Heat Storage and Buffering
• 5.15 System Integration
• 5.16 Appendix
  • 5.16.1 Worksheet B – Heat Emitters and Pipework – Blank.
  • 5.16.2 Worksheet B – Heat Emitters and Pipework – Instructions
  • 5.16.3 Worksheet C – Water Content of System – Blank
  • 5.16.4 Worksheet C – Water Content of System – Instructions

The Domestic heating design guide is published by the Domestic Building Services Panel (www.dbsp.co.uk), a joint initiative of the heating industry and the Chartered Institution of Building Services Engineers.

Members of the Domestic Building Services Panel or representatives of educational institutions wishing to make bulk purchases should email [email protected] or call +44 (0)20 8772 3618.