{"id":379499,"date":"2024-10-20T03:02:43","date_gmt":"2024-10-20T03:02:43","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/bs-52502021\/"},"modified":"2024-10-26T05:27:59","modified_gmt":"2024-10-26T05:27:59","slug":"bs-52502021","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/bsi\/bs-52502021\/","title":{"rendered":"BS 5250:2021"},"content":{"rendered":"

This British Standard gives recommendations for the management of moisture in buildings using an integrated and pragmatic approach. This includes the management of moisture risk from interstitial and surface condensation, from too high or too low internal relative humidity, and from rain penetration or high levels of ground water. It covers all states of water as gas, liquid and solid, and the interactions between these states. It describes the principal sources of moisture in buildings, its transportation and deposition and provides recommendations and guidance on how to manage those risks during the assessment, design, construction and operation of buildings.<\/p>\n

This British Standard does not cover measures specifically dealing with flooding and escape of water. These are dealt with in BS 85500.<\/p>\n

This British Standard is intended for use by designers, builders and users of any class of building. This standard gives guidance on risks of all sorts from high moisture levels, whether in the building fabric or in indoor air, which can endanger the health and well\u2011being of building occupants and the integrity of the building fabric.<\/p>\n

This British Standard is relevant to buildings of all types, whatever their form, construction and occupancy, both new and existing, and both domestic and non-domestic, except for buildings used for storage at sub-zero temperatures.<\/p>\n

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PDF Pages<\/th>\nPDF Title<\/th>\n<\/tr>\n
7<\/td>\nForeword <\/td>\n<\/tr>\n
9<\/td>\nIntroduction <\/td>\n<\/tr>\n
12<\/td>\nSection 1: General
1 Scope
2 Normative references <\/td>\n<\/tr>\n
13<\/td>\n3 Terms, definitions and abbreviated terms
3.1 Terms and definitions <\/td>\n<\/tr>\n
16<\/td>\n3.2 Abbreviated terms <\/td>\n<\/tr>\n
17<\/td>\nSection 2: Design and guidance to avoid moisture related problems
4 Design to avoid moisture related problems
4.1 Assessing the likelihood of condensation <\/td>\n<\/tr>\n
18<\/td>\n4.2 Methods of assessment <\/td>\n<\/tr>\n
19<\/td>\n4.3 Internal climate <\/td>\n<\/tr>\n
20<\/td>\n4.4 External climate (condensation risk) <\/td>\n<\/tr>\n
21<\/td>\n4.5 The external envelope <\/td>\n<\/tr>\n
24<\/td>\n4.6 Alterations and extensions to buildings
5 Guidance for builders and owners <\/td>\n<\/tr>\n
25<\/td>\n6 Remedial works
6.1 Actions to manage moisture risk
6.2 Heating
6.3 Ventilation <\/td>\n<\/tr>\n
26<\/td>\nSection 3: Design principles \u2013 Building services
7 Application of design principles \u2013 Heating
7.1 General
7.2 Warm air heating <\/td>\n<\/tr>\n
27<\/td>\n7.3 Electric storage heaters
7.4 Unflued oil and gas heaters
7.5 Heating controls <\/td>\n<\/tr>\n
28<\/td>\n8 Application of design principles \u2013 Occupied space ventilation
8.1 General <\/td>\n<\/tr>\n
29<\/td>\n8.2 Natural ventilation <\/td>\n<\/tr>\n
30<\/td>\n8.3 Continuous mechanical ventilation <\/td>\n<\/tr>\n
31<\/td>\n8.4 Cooker hood (range hood) <\/td>\n<\/tr>\n
32<\/td>\n8.5 Purge ventilation
8.6 Drying rooms\/cupboards
8.7 Dehumidifiers <\/td>\n<\/tr>\n
33<\/td>\nSection 4: Design principles \u2013 fabric details
9 Application of design principles \u2013 junctions
9.1 Heat loss and surface temperatures <\/td>\n<\/tr>\n
34<\/td>\n9.2 Principles for reducing the effects of thermal bridging
10 Application of design principles \u2013 Floors
10.1 General <\/td>\n<\/tr>\n
35<\/td>\nFigure 1 \u2014 Key to the figures
10.2 Categories of floors <\/td>\n<\/tr>\n
36<\/td>\nTable 1 \u2014 Summary of floor constructions
10.3 Groundbearing floors with DPM <\/td>\n<\/tr>\n
37<\/td>\nFigure 2 \u2014 Connective\/systemic effects for groundbearing floors <\/td>\n<\/tr>\n
39<\/td>\nFigure 3 \u2014 Insulation above concrete slab
Figure 4 \u2014 Insulation below concrete slab
10.4 Groundbearing floor without DPM, with or without insulation either above or below the floor slab\/tiles <\/td>\n<\/tr>\n
42<\/td>\nFigure 5 \u2014 Existing groundbearing floors either without DPM or without insulation above or below the floor
10.5 Suspended floors <\/td>\n<\/tr>\n
44<\/td>\nFigure 6 \u2014 Connective\/systemic effects for suspended floors <\/td>\n<\/tr>\n
46<\/td>\nFigure 7 \u2014 Suspended concrete floor with insulation above the floor slab
Figure 8 \u2014 Suspended concrete floor with insulation below the floor slab <\/td>\n<\/tr>\n
47<\/td>\nFigure 9 \u2014 Suspended timber floor with insulation above the joists
Figure 10 \u2014 Suspended timber floor with insulation between the joists <\/td>\n<\/tr>\n
48<\/td>\nFigure 11 \u2014 Timber suspended floor with a soffit of high vapour resistance
10.6 Basements <\/td>\n<\/tr>\n
51<\/td>\n11 Application of design principles \u2013 Walls
11.1 General <\/td>\n<\/tr>\n
52<\/td>\nTable 2 \u2014 Checklist for design principles \u2013 Walls <\/td>\n<\/tr>\n
58<\/td>\nFigure 12 \u2014 Key to the figures
11.2 Categories of walls
Table 3 \u2014 Index of wall types <\/td>\n<\/tr>\n
59<\/td>\n11.3 Masonry walls <\/td>\n<\/tr>\n
64<\/td>\nFigure 13 \u2014 Solid traditional masonry wall \u2013 areas to inspect <\/td>\n<\/tr>\n
66<\/td>\nFigure 14 \u2014 Existing solid masonry wall with external wall insulation \u2013 window details
Figure 15 \u2014 Existing solid masonry wall with external wall insulation \u2013 wall-roof <\/td>\n<\/tr>\n
67<\/td>\nFigure 16 \u2014 Existing solid masonry wall with external wall insulation \u2013 parapet detail
Figure 17 \u2014 Existing solid masonry wall \u2013 external insulation [Example of below damp\u2011proofing course (DPC) or joist ends] <\/td>\n<\/tr>\n
68<\/td>\nFigure 18 \u2014 Solid masonry wall \u2013 external insulation
Figure 19 \u2014 External wall insulation to roof \u2013 detail <\/td>\n<\/tr>\n
69<\/td>\nFigure 20 \u2014 External wall insulation at window \u2013 detail
Figure 21 \u2014 External wall insulation to ground level \u2013 detail <\/td>\n<\/tr>\n
70<\/td>\nFigure 22 \u2014 Recessed window head \u2013 detail <\/td>\n<\/tr>\n
71<\/td>\nFigure 23 \u2014 Existing solid masonry wall with internal wall insulations \u2013 key considerations before and during installation <\/td>\n<\/tr>\n
73<\/td>\nFigure 24 \u2014 Solid masonry wall \u2013 internal insulation at window \u2013 reducing thermal bridging
Figure 25 \u2014 Solid masonry wall \u2013 internal insulation at joists \u2013 reducing thermal bridging <\/td>\n<\/tr>\n
77<\/td>\nFigure 26 \u2014 Cavity masonry wall \u2013 insulation at junction with window frames
Figure 27 \u2014 Cavity masonry wall \u2013 insulation at junction with roof (Example of eaves and continuous insulation) <\/td>\n<\/tr>\n
78<\/td>\n11.4 Framed walls <\/td>\n<\/tr>\n
81<\/td>\nFigure 28 \u2014 Framed wall \u2013 external insulation <\/td>\n<\/tr>\n
82<\/td>\nFigure 29 \u2014 Framed wall \u2013 lintel and sill <\/td>\n<\/tr>\n
83<\/td>\nFigure 30 \u2014 Framed wall \u2013 junction with bearing floor <\/td>\n<\/tr>\n
84<\/td>\nFigure 31 \u2014 Framed wall \u2013 junction with roof \u2013 continuous insulation <\/td>\n<\/tr>\n
85<\/td>\nFigure 32 \u2014 Framed wall \u2013 internal insulation <\/td>\n<\/tr>\n
86<\/td>\nFigure 33 \u2014 Framed wall \u2013 internal sheathing \u2013 thermal insulation between and to the inside of the structural framing
Figure 34 \u2014 Framed wall \u2013 external sheathing \u2013 thermal insulation between and to the inside of the structural framing <\/td>\n<\/tr>\n
87<\/td>\nFigure 35 \u2014 Framed wall \u2013 external sheathing \u2013 thermal insulation between the framing and on the outside of the sheathing <\/td>\n<\/tr>\n
90<\/td>\n11.5 Structural insulated panel systems (SIPS): walls <\/td>\n<\/tr>\n
92<\/td>\n11.6 Cladding systems <\/td>\n<\/tr>\n
94<\/td>\nFigure 36 \u2014 Cladding systems \u2013 Integral thermal insulation \u2013 Prefabricated <\/td>\n<\/tr>\n
95<\/td>\nFigure 37 \u2014 Cladding systems \u2013 Integral thermal insulation \u2013 Built in situ <\/td>\n<\/tr>\n
97<\/td>\nFigure 38 \u2014 Closed joint rainscreen cladding <\/td>\n<\/tr>\n
98<\/td>\nFigure 39 \u2014 Open joint rainscreen cladding
11.7 Cavity trays and weep holes <\/td>\n<\/tr>\n
100<\/td>\n11.8 Openings in walls
12 Application of design principles \u2013 Roofs
12.1 General <\/td>\n<\/tr>\n
101<\/td>\nFigure 40 \u2014 Key to the figures
12.2 Categories of roofs <\/td>\n<\/tr>\n
103<\/td>\nFigure 41 \u2014 Roofs categorized by position of the insulation
12.3 Methods for assessing moisture risks in roofs <\/td>\n<\/tr>\n
104<\/td>\nTable 4 \u2014 Calculation methods for different roof types <\/td>\n<\/tr>\n
105<\/td>\n12.4 Design considerations <\/td>\n<\/tr>\n
108<\/td>\n12.5 Cold pitched roofs <\/td>\n<\/tr>\n
112<\/td>\nFigure 42 \u2014 Cold pitched roof \u2013 LR underlay \u2013 Air permeable outer weatherproof covering
Figure 43 \u2014 Cold pitched roof \u2013 LR underlay \u2013 Air impermeable outer weatherproof covering <\/td>\n<\/tr>\n
113<\/td>\nTable 5 \u2014 Minimum free area of openings for loft-space ventilation <\/td>\n<\/tr>\n
114<\/td>\n12.6 Warm pitched roofs <\/td>\n<\/tr>\n
116<\/td>\nFigure 44 \u2014 Warm pitched roof with HR underlay \u2013 Any roof covering <\/td>\n<\/tr>\n
117<\/td>\nFigure 45 \u2014 Warm pitched roof with LR underlay and air permeable outer weatherproof covering
Figure 46 \u2014 Warm pitched roof with LR underlay and air impermeable outer weatherproof covering <\/td>\n<\/tr>\n
118<\/td>\n12.7 Hybrid pitched roofs
Figure 47 \u2014 Routing insulation and AVCL in a hybrid pitched roof to achieve continuity \u2013 insulation follows slope of roof and horizontal ceiling <\/td>\n<\/tr>\n
119<\/td>\nFigure 48 \u2014 Routing insulation and AVCL in a hybrid pitched roof to achieve continuity \u2013 insulation follows horizontal ceiling, vertical wall and slope of roof
12.8 Flat roofs <\/td>\n<\/tr>\n
121<\/td>\nFigure 49 \u2014 Cold flat roof \u2013 roof deck <\/td>\n<\/tr>\n
122<\/td>\nFigure 50 \u2014 Warm flat roof \u2013 roof deck
Figure 51 \u2014 Warm flat roof \u2013 roof slab <\/td>\n<\/tr>\n
123<\/td>\nFigure 52 \u2014 Inverted flat roof \u2013 roof deck
Figure 53 \u2014 Inverted flat roof \u2013 roof slab <\/td>\n<\/tr>\n
124<\/td>\nFigure 54 \u2014 Cold pitched roof with flat roof apex
12.9 Self-supporting sheeted metal <\/td>\n<\/tr>\n
127<\/td>\nFigure 55 \u2014 Site-assembled metal roof <\/td>\n<\/tr>\n
128<\/td>\nFigure 56 \u2014 Composite metal roof
12.10 Structural insulated panel systems (SIPS): pitched roofs and flat roofs <\/td>\n<\/tr>\n
131<\/td>\n12.11 Openings in roofs
12.12 Refurbishment <\/td>\n<\/tr>\n
133<\/td>\nSection 5: Condensation risk
13 Calculating condensation risk
13.1 Mould growth and surface condensation <\/td>\n<\/tr>\n
134<\/td>\n13.2 Assessment methods <\/td>\n<\/tr>\n
136<\/td>\nTable 6 \u2014 Monthly mean temperature and relative humidity for interstitial condensation calculations
Table 7 \u2014 Corrections to monthly mean temperatures and relative humidities to create condensation risk years with various return periods <\/td>\n<\/tr>\n
138<\/td>\nTable 8 \u2014 Example of the calculation of estimated ground temperatures <\/td>\n<\/tr>\n
139<\/td>\nTable 9 \u2014 Moisture production rates in housing
Table 10 \u2014 Typical moisture production rates from fuels <\/td>\n<\/tr>\n
140<\/td>\nTable 11 \u2014 Typical moisture generation rates for household activities <\/td>\n<\/tr>\n
141<\/td>\nFigure 57 \u2014 Variation of internal humidity classes with external temperature
Table 12 \u2014 Internal humidity classes: building types and limiting relative humidities at T3 = 0 \u00b0C <\/td>\n<\/tr>\n
142<\/td>\n13.3 Calculation of condensation risk in a cold pitched roof with thermal insulation applied on a horizontal ceiling <\/td>\n<\/tr>\n
143<\/td>\nAnnex A (informative)\u2002 Guidance for designers and builders: a whole\u2011building approach <\/td>\n<\/tr>\n
148<\/td>\nAnnex B (informative)\u2002 Properties of materials <\/td>\n<\/tr>\n
149<\/td>\nTable B.1 \u2014 Thermal conductivity and vapour resistivity of building materials <\/td>\n<\/tr>\n
152<\/td>\nTable B.2 \u2014 Vapour resistances of thin membranes and foils <\/td>\n<\/tr>\n
153<\/td>\nTable B.3 \u2014 Thermal resistance, in m2K\/W, unventilated cavities 5 mm and 25 mm wide with high emissivity surfaces <\/td>\n<\/tr>\n
154<\/td>\nTable B.4 \u2014 Thermal resistance of roof spaces
Table B.5 \u2014 Thermal resistances of surfaces <\/td>\n<\/tr>\n
155<\/td>\nTable B.6 \u2014 Factors for converting permeance units to \u00b5g\/N\u00b7s
Annex C (informative)\u2002 Diagnosis of dampness problems <\/td>\n<\/tr>\n
162<\/td>\nAnnex D (informative)\u2002 Moisture in buildings <\/td>\n<\/tr>\n
165<\/td>\nTable D.1 \u2014 Effect of condensate on impermeable surfaces
Annex E (informative)\u2002 Guidance for builders <\/td>\n<\/tr>\n
167<\/td>\nAnnex F (informative)\u2002 Guidance for occupiers on how to avoid damaging condensation <\/td>\n<\/tr>\n
169<\/td>\nAnnex G (informative)\u2002 The temperature and moisture content of air <\/td>\n<\/tr>\n
170<\/td>\nFigure G.1 \u2014 Psychrometric chart showing the derivation of relative humidity from temperature and vapour pressure <\/td>\n<\/tr>\n
173<\/td>\nBibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

Management of moisture in buildings. Code of practice<\/b><\/p>\n\n\n\n\n
Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
BSI<\/b><\/a><\/td>\n2021<\/td>\n178<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":379508,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[1270,2641],"product_tag":[],"class_list":{"0":"post-379499","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-91-120-99","7":"product_cat-bsi","9":"first","10":"instock","11":"sold-individually","12":"shipping-taxable","13":"purchasable","14":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/379499","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/379508"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=379499"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=379499"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=379499"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}