Imposed Loads on Buildings
6.1 Design situations
General Requirements
The imposed loads shall be determined for each relevant design situation.
For the selection of design situations see EN 1990:2023, 5.2
Fatigue and Dynamic Considerations
Where the number of load variations or the effects of vibrations can cause fatigue, a fatigue load model should be established.
For structures susceptible to vibrations, dynamic models of imposed loads should be considered where relevant.
- For dynamic actions, see EN 1990 and the additional provisions given in 6.2.2
- For dynamic loads caused by machinery, see EN 1991-3
6.2 Classification
6.2.1 General
Imposed loads shall be classified as free variable actions, unless otherwise specified in this standard.
For the classification of actions, see EN 1990:2023, 6.1.1
- For the treatment of the dynamic part of a quasi-static action, see EN 1990:2023, 7.1.3(5)
- For synchronized rhythmic crowd loads, see 6.2.2
According to EN 1990, for specific types of structures or structural members having typical mass and damping properties, the acceleration limits can be assumed met when the natural frequency of vibrations is kept above appropriate values. For relevant limits and values, see EN 1990:2023, A.1.8.3.
6.2.2 Additional provisions for dynamic actions
If resonance effects from synchronised rhythmic crowd loads cannot be neglected (see 6.2.1(4)), a more refined analysis of the dynamic response of the structure should be performed according to EN 1990, the relevant parts of EN 1991 and the other Eurocodes.
- See also EN 1990:2023, A.1.8.3
- Further information on the procedure to be used for structures that are susceptible to dynamic excitation can be given in the National Annex
Fluctuating effects are taken into account by a dynamic amplification factor φ which is applied to the static load values, as shown in Formula (6.4).
6.3 Representation of actions
For the determination of the imposed loads, floor and roof areas in buildings should be sub-divided into categories according to their use, see 6.5.2.
6.4 Load arrangements
6.4.1 Floors, beams and roofs
For the design of a floor structure within one storey or a roof, the imposed load shall be taken into account as a free action applied at the most unfavourable part of the influence area of the action effects considered. For the other storeys, imposed loads may be assumed to be distributed uniformly (fixed actions) on the whole storey area.
- This is a simplified rule compared to the most critical (‘chess board’) loading arrangement
- Characteristic values of uniformly distributed imposed loads are given in 6.5
Characteristic values of concentrated loads are given in 6.5.
αₐ according to 6.5.3.2.
6.4.2 Columns and walls
For the design of columns and walls, the imposed load should be placed at all unfavourable locations in order to calculate the most adverse (combination of) effects of actions.
Where imposed loads from several storeys act on columns and walls, the maximum axial force may be calculated assuming the imposed loads on each storey to be uniformly distributed.
Where imposed loads from several storeys act on columns and walls, the imposed loads may be reduced by a factor αₙ according to 6.5.3.2.
6.5 Characteristic values of imposed loads
6.5.1 Field of application
This clause covers values of imposed loads on buildings due to:
- Normal use by persons
- Furniture and moveable objects (e.g. partitions, storage, the contents of containers)
- Vehicles
- Anticipating events, such as concentrations of persons or of furniture, or the moving or stacking of objects which may occur during reorganization or redecoration
The imposed loads specified in this part are modelled by uniformly distributed loads, line loads or concentrated loads or combinations of these loads.
Heavy equipment (e.g. in communal kitchens, radiology rooms, boiler rooms, etc.) are not included in the loads given in this clause. Loads for heavy equipment should be as specified by the relevant authority or, where not specified, agreed for a specific project by the relevant parties.
6.5.2 Categories of use and characteristic values
Imposed loads on buildings shall be divided into categories according to the specific use of the area under consideration.
The categories are those given in Table 6.1 (NDP) unless the National Annex provides sub-categories and/or additional categories.
qₖ (uniformly distributed load) and/or Qₖ (concentrated load).
qₖ is intended for determination of general effectsQₖ is intended for local effects and not expected to be combined with qₖ unless otherwise stated- See also 6.4.1(2) for local verifications
Qₖ shall be considered to act at any point on the floor, roof, balcony, terrace, staircase over an area with a shape which is appropriate to their use and form.
The contact surface is normally assumed as a square, see Table 6.1 (NDP) for the dimension of the loaded area.
See 6.2.2 for additional provisions on dynamic actions.
Table 6.1 - Categories of use and values for qₖ and Qₖ
| Category | Specific Use | Sub-categories with examples | qₖ [kN/m²] | Qₖ [kN] | Typical dimension of loaded area (m × m) |
|---|
| A | Areas for domestic and residential activities | | | | |
| | A1 Rooms in residential buildings and houses, including corridors | 2.0 | 2.0 | 0.05 × 0.05 |
| | A2 Bedrooms, wards, dormitories, private bathrooms and toilets in hospitals, hotels, hostels and other institutional residential occupancies | 2.0 | 2.0 | 0.05 × 0.05 |
| B | Public areas (not susceptible to crowding) | | | | |
| | B1 Office areas for general use including corridors other than archive/storage areas (see Category E) | 3.0 | 3.0 | 0.05 × 0.05 |
| | B2 Kitchens, communal bathrooms and toilets in hospitals, hotels, hostels and other institutional residential occupancies | 3.0 | 3.0 | 0.05 × 0.05 |
| C | Public areas where people can congregate | | | | |
| | C1: Areas with tables, e.g. schools, cafés, restaurants, dining halls, reading rooms, receptions | 3.0 | 4.0 | 0.05 × 0.05 |
| | C2: Areas with fixed seats, e.g. churches, theatres, cinemas, conference rooms, lecture halls, assembly halls, waiting rooms | 4.0 | 4.0 | 0.05 × 0.05 |
| | C3: Areas without obstacles for moving people, e.g. museums, exhibition rooms, corridors | 5.0 | 4.0 | 0.05 × 0.05 |
| | C4: Areas with possible physical activities, e.g. dance halls, gymnastic rooms, stages | 5.0 | 7.0 | 0.05 × 0.05 |
| | C5: Areas susceptible to large crowds, e.g. concert halls, sports halls including stands, railway platforms | 7.5 | 4.5 | 0.05 × 0.05 |
| D | Shopping areas | | | | |
| | D1: Areas in retail shops | 4.0 | 4.0 | 0.05 × 0.05 |
| | D2: Areas in department stores | 5.0 | 7.0 | 0.05 × 0.05 |
| E | Areas for archive, storage and industrial use | | | | |
| | E1: Areas susceptible to accumulation of goods, including access areas | 7.5 | 7.0 | See footnotes |
| | E2: Industrial use | See footnotes | | |
| F | Garages and vehicle traffic areas | | | | |
| | F1 Traffic and parking areas for light vehicles (≤ 8 seats not including driver) | 2.5 | 20 | See footnotes |
| G | Garages and vehicle traffic areas (medium/heavy) | | | | |
| | G1 Traffic and parking areas for medium vehicles (on 2 axles) | 5.0 | 90 | 0.2 × 0.2 |
| | G2 Traffic and parking areas for heavy vehicles | See footnotes | | |
| H | Roofs not accessible except for normal maintenance and repair | | 0.4 | 1.0 | 0.05 × 0.05 |
| I | Roofs accessible with occupancy according to categories A to G | | See categories A to G | | |
| K | Roofs accessible for special services | | 5.0 | See Table 6.4 | |
| S | Stairs and landings | | | | |
| | S1 Stairs and landings to areas belonging to category A1 and B1 | See categories A1 and B1 | | 0.05 × 0.05 |
| | S2 Stairs and landings for tribunes without fixed seats that are defined as escape ways | 7.5 | 3.0 | 0.05 × 0.05 |
| | S3 Stairs and landings not belonging to category S1 or S2 | 5.0 | 2.0 | 0.05 × 0.05 |
| T | Terraces and balconies | | | | |
| | T1 Roof terraces, access balconies, balconies, loggias, etc. | 3.0 | 2.0 | 0.05 × 0.05 |
Important footnotes:
- Specific imposed loading and their impact area may be specified by the relevant authority or agreed for a specific project
- Attention is drawn to dynamic effects, particularly for C4 and C5 categories
- For loadings on grandstands and stages, see 6.5.3.4
- For industrial use, see also 6.5.4
- For heavy vehicles, see also EN 1991-2
6.5.3 Residential, social, commercial and administration areas (categories A to D)
6.5.3.1 Partitions treated as imposed loads
The self-weight of partitions may be taken into account by introducing a uniformly distributed load qₖ,p provided that the following conditions are verified:
- The relevant floor allows a sufficient distribution of a line load orthogonal to the intended orientation of the partition
- The self-weight of the partition is
Qₖ,p ≤ 3.0 kN/m wall length
Partitions are elements other than structural; as such, according to 5.2(2), they are expected to be classified as permanent actions, typically free for their spatial variation. The simplified approach provided here only applies when the conditions defined above are verified. See section (4) for heavier partitions.
qₖ,p should be added to the imposed loads of floors obtained from 6.5.2(2).
The value of this uniformly distributed load qₖ,p for partitions with a self-weight Qₖ,p ≤ 3.0 kN/m wall length should be based on the self-weight of the partitions.
Formula (6.1):
qₖ,p = max{0.35 kN/m²; (0.4/m) Qₖ,p}
Qₖ,p is expressed in kN/m wall lengthqₖ,p is expressed in kN/m²
The National Annex can set specific rules to derive the value of the uniformly distributed load qₖ,p for partitions with a self-weight Qₖ,p > 3.0 kN/m wall length.
6.5.3.2 Reduction factors
The reduction factors αₐ and αₙ specified in this clause, which are applicable to the qₖ values for imposed loads, may be used if specified by the relevant authority, or, where not specified, as agreed for a specific project by the relevant parties.
αₐ is the reduction factor relevant to imposed loads on floors, beams and roofsαₙ is the reduction factor relevant to columns and walls depending on the number of storeys above such columns and walls
αₐ and αₙ may be mutually combined when dealing with multi-storey buildings.
The reduction factors αₐ and αₙ can be mutually combined provided that the product αₐ × αₙ is not less than 0.50 unless the National Annex gives different rules.
The reduction factors αₐ and αₙ should not be applied for accidental and seismic design situations, including fire.
αₐ may be applied to the qₖ values for imposed loads for floors, beams and accessible roofs.
Formula (6.2) - Area reduction factor:
With the restriction for categories C and D: αₐ ≥ 0.6
Where A is the tributary area expressed in m².
For continuous structures, the reduction factor αₐ generally differs from span to span. As a simplification, the same value can apply uniformly using the maximum of the αₐ values calculated for different tributary areas.
αₙ.
Formula (6.3) - Number of floors reduction factor:
Where αₙ is calculated for each floor considering the number of floors n above the column or wall under consideration.
When the imposed load is applied as an accompanying action in accordance with EN 1990, the combination of the factors ψ (EN 1990:2023, Table A.1.7) and αₙ may be considered.
The two factors ψ and αₙ can be combined, unless the National Annex gives different rules.
6.5.3.3 Actions induced by forklifts
The vertical loads on floors due to traffic of forklifts shall be taken into account according to 6.5.4.2.
6.5.3.4 Grandstands and stages
Loadings on grandstands should take account of loads from spectators, fixed and movable equipment, and any dynamic loads caused by people dancing, jumping or moving in a synchronized manner.
For barrier and handrail loadings for grandstands, see 6.6.
- The minimum vertical static equivalent load is 5 kN/m² unless the National Annex gives a different value
- The minimum notional horizontal load is 5% of the design vertical imposed load applied to the area of stage floor on which the activity takes place, unless the National Annex gives different values
- The minimum notional horizontal load is 2.5% of the design vertical imposed load for other parts of the stage floor (for example areas used for workers and equipment) unless the National Annex gives a different value
- The notional horizontal loads are typically applied in combination with wind loads and not combined with horizontal loads that take account of the geometric imperfections of frames
6.5.4 Areas for archive, storage and industrial activities (category E)
6.5.4.1 Load model
The characteristic value of the imposed load in areas for storage and industrial activities shall be the maximum value taking account of the dynamic effects if appropriate. The loading arrangement shall be defined so that it produces the most unfavourable conditions allowed in use.
For transient design situations due to installation and reinstallation of machines, production units, etc. guidance is given in EN 1991-1-6.
See Annex A for specific weights.
6.5.4.2 Actions induced by forklifts
Forklifts should be classified in six classes FL 1 to FL 6 depending on net weight, dimensions and hoisting loads, see Table 6.2.
Table 6.2 - Dimensions of forklift according to classes FL
| Class | Net weight [kN] | Hoisting load [kN] | Width of axle [m] | Overall width [m] | Overall length [m] |
|---|
| FL 1 | 21 | 10 | 0.85 | 1.00 | 2.60 |
| FL 2 | 31 | 15 | 0.95 | 1.10 | 3.00 |
| FL 3 | 44 | 25 | 1.00 | 1.20 | 3.30 |
| FL 4 | 60 | 40 | 1.20 | 1.40 | 4.00 |
| FL 5 | 90 | 60 | 1.50 | 1.90 | 4.60 |
| FL 6 | 110 | 80 | 1.80 | 2.30 | 5.10 |
The static characteristic value of the vertical axle load Qₖ of a forklift should be obtained from Table 6.3 depending on the forklift classes.
Table 6.3 - Axle loads of forklifts
| Class of forklifts | Axle load Qₖ [kN] |
|---|
| FL 1 | 26 |
| FL 2 | 40 |
| FL 3 | 63 |
| FL 4 | 90 |
| FL 5 | 140 |
| FL 6 | 170 |
The static characteristic value of the vertical axle load Qₖ should be increased by the dynamic amplification factor φ using Formula (6.4) to derive the characteristic value of the dynamic action Qₖ,dyn:
Formula (6.4):
The dynamic amplification factor φ for forklifts takes into account the inertial effects caused by acceleration and deceleration of the hoisting load.
- φ = 1.40 for pneumatic tyres
- φ = 2.00 for solid tyres
For forklifts having a net weight greater than 110 kN the loads should be defined by a more accurate analysis.
Horizontal loads due to acceleration or deceleration of forklifts may be taken as 30% of the vertical axle loads Qₖ. Dynamic factors may be neglected.
6.5.4.3 Actions induced by transport vehicles
The actions from transport vehicles that move on floors freely or guided by rails should be determined by a pattern of wheel loads.
The static values of the vertical wheel loads should be given based on gross vehicle weight. Their spectra should be used to define combination factors and fatigue loads.
The load arrangements including the vertical and horizontal wheel loads and the dimensions relevant for the design should be as specified by the relevant authority or, where not specified, agreed for a specific project by the relevant parties.
- Where relevant, see traffic load models from EN 1991-2
- For accidental design situations where impact from vehicles or accidental loads from machines can be relevant, see EN 1991-1-7 and EN 1991-2
6.5.4.4 Actions induced by special devices for maintenance
Special devices for maintenance should be modelled as loads from transportation vehicles, see 6.5.4.3.
The load arrangements including the vertical and horizontal wheel loads and the dimensions relevant for the design should be as specified by the relevant authority or, where not specified, agreed for a specific project by the relevant parties.
6.5.5 Garages and vehicle traffic areas (categories F and G)
The load model which should be used for garages and vehicle traffic areas (excluding ordinary roads and bridges) is a single axle with a load Qₖ with dimensions according to Figure 6.5 and/or a uniformly distributed load qₖ.
- The characteristic values for
qₖ and Qₖ and the size of the loaded area, a, are given in Table 6.1 (NDP). See also 6.5.2(2)
- Where areas are designed to category F or G, it can be relevant to control access of vehicles to those areas, for example by physical means or appropriate warning signs
Qₖ should be in the possible positions which will produce the most adverse effects of the action.
6.5.6 Roofs (categories H to K)
6.5.6.1 General rules
For roofs, the simultaneity of imposed loads with climatic actions should be considered where appropriate.
The National Annex can set specific rules for treatment of simultaneity of imposed loads with climatic actions (particularly for category H roofs).
6.5.6.2 Roofs not accessible except for normal maintenance and repair (category H)
For roofs of category H, the characteristic value qₖ shall be applied on a defined area Aᵣₑf of the roof at the most unfavourable position of the influence area of the action effects considered (see 6.4 for load arrangements).
- For category H,
qₖ can be varied by the National Annex dependent upon the roof slope
- The area
Aᵣₑf is equal to 10 m² unless the National Annex gives a different value and specific rules to consider the maintenance and repair conditions that are expected
6.5.6.3 Roofs accessible for special services (category K)
For roofs of category K, which are accessible for special services such as classes HC helicopter landing areas, to take account of dynamic effects during take-off and landing, the concentrated actions from helicopters on landing areas should be determined using Formula (6.4) and the dynamic amplification factor φ = 1.40.
- The dynamic amplification factor φ = 1.40 excludes accidental loadings, which are covered in EN 1991-1-7
Qₖ is taken from Table 6.4 (NDP) according to the class of the helicopter unless the National Annex gives different values
Table 6.4 - Imposed loads on roofs of category K for helicopters
| Class of helicopter | Take-off load Q of helicopter | Take-off load Qₖ | Dimension of loaded area (m × m) |
|---|
| HC1 | Q ≤ 20 kN | Qₖ = 20 kN | 0.2 × 0.2 |
| HC2 | 20 kN < Q ≤ 60 kN | Qₖ = 60 kN | 0.3 × 0.3 |
| HC3 | 60 kN < Q ≤ 120 kN | Qₖ = 120 kN | 0.3 × 0.3 |
6.5.6.4 Access ladders and walkways
Access ladders and walkways should be assumed to be loaded according to category H for a roof slope < 20°.
For walkways which are part of a designated escape route, qₖ should be according to categories A to D as relevant.
For walkways for service, a minimum characteristic value Qₖ of 1.5 kN should be taken.
6.5.6.5 Frames and coverings of access hatches, supports of ceilings
The following loads should be used for the design of frames and coverings of access hatches (other than glazing), the supports of ceilings and similar structures:
- Without access: no imposed load
- With access: 0.25 kN/m² distributed over the whole area or the area supported, and the concentrated load of 0.9 kN so placed so as to produce maximum stresses in the affected member
6.5.7 Stairs and landings (category S)
The characteristic values for qₖ and Qₖ that are given in 6.5.2 should not be lower than the values of the adjacent areas, which give access to the stairs and landings under consideration.
6.5.8 Terraces and balconies (category T)
The characteristic values for qₖ and Qₖ that are given in 6.5.2 should not be lower than the values of the adjacent areas, which give access to the terrace or balcony under consideration.
Imposed loads on terraces and balconies are usually not applied with snow loads, see also 6.5.6.1 for simultaneity of imposed loads and climatic actions.
6.6 Barrier loadings
6.6.1 General
Barriers should be designed for both horizontal and vertical imposed loads.
6.6.2 Horizontal loads
The characteristic values of the line load qₖ shall be applied at the height of the barriers (except guard rails for areas only accessible for maintenance and repair) but not higher than 1.2 m.
- The characteristic values of the line load
qₖ are given in Table 6.5 (NDP) unless the National Annex gives different values
- The National Annex can prescribe additional concentrated loads
Qₖ and related loaded area, and/or hard or soft body impact specifications for analytical or experimental verification
Table 6.5 - Horizontal loads on barriers
| Category | Specific Use | qₖ [kN/m] |
|---|
| A | Areas for domestic and residential activities | 0.8 |
| B | Public areas (not susceptible to crowding) | 0.8 |
| C1 | Areas with tables | 1.0 |
| C2 | Areas with fixed seats | 1.0 |
| C3 | Areas without obstacles for moving people | 1.0 |
| C4 | Areas with possible physical activities | 1.0 |
| C5 | Areas susceptible to large crowds | 3.0 |
| D | Shopping areas | 1.0 |
| E | Areas for archive, storage and industrial use | 2.0 |
| F | Garages and vehicle traffic areas (≤ 30 kN) | See EN 1991-1-7 |
| G | Garages and vehicle traffic areas (> 30 kN) | See EN 1991-1-7 |
| H | Roofs not accessible except for maintenance | 0.8 |
| I | Roofs accessible with occupancy A to G | See categories A to G |
| K | Roofs accessible for special services | 1.0 |
| S | Stairs and landings | See categories A to G |
| T | Balconies and terraces | See categories A to G |
For areas of category E, the horizontal loads depend on the occupancy. Therefore, the value of qₖ is defined as a minimum value and should be checked for the specific occupancy and actual storage conditions.
Qₖ at any point.
The value of Qₖ is 0.3 kN unless a different value is given in the National Annex.
- The geometric arrangement of the structure
- Typical movements of spectators in a direction parallel or perpendicular to the barrier
- Specific areas of grandstands such as the front row, the rear of the stand, adjacent to the barrier and the standing area
6.6.3 Vertical loads
Barriers should be designed for a vertical load, which is either a concentrated load Qₖ or a uniformly distributed load qₖ, whichever gives the most adverse design condition in combination with the horizontal loading given in 6.6.2.
The value of Qₖ is 1 kN and the value for qₖ is 0.6 kN/m unless different values are given in the National Annex.