Wentworth House
21,331 sq ft

Wentworth House

Maris Expertise
Maris has conducted an extensive office design and optimisation project for potential new offices for Majestic Wine.

The building is constructed with a framed structure with cavity brick / blockwork external walls and powder coated double glazed windows. The superstructure comprises a steel frame, with concrete floor slabs on metal decking.

Floor Loading
• Assumed offices 3.5KN/m2 (+1KN for partitioning)
• Assumed plant enclosures 7.5KN/m2


Windows and main external doors are all powder coated aluminium units with double glazed sealed units.

The roof construction comprises of a steel frame construction, clad in metal sheeting and weathered in artificial slates. Abutments have lead lined valley gutters and lead flashings.

Column grid 7.5m – 10.5m centres
Raised floor zone 100mm
Floor to ceiling 3,360mm, 2,800mm, 2,700mm
Slab to slab height 3,970mm – 3,300mm

Noise Rating
This property is presumed to comply with the following noise ratings:
Offices (open plan) NR38
Reception NR40
WC areas NR40

These ratings are industry recognised standards and provide a low level of noise emission from the base build services.

WC / Bathroom Facilities
WC bathroom facilities are on the ground and 2nd floors. The WCs are finished with ceramic tile finish to the floors and walls in the main wash-hand basin area. Ceramic wash-hand basins are set on vanity units. The ceiling is a suspended ceiling grid and tiles. All sanitary ware is glazed white ceramic with a chrome finish.

Raised Floors
Medium grade, full accessible raised floors are provided throughout the floor. Floor tiles are 600mm x 600mm wrapped galvanised steel. Floor voids are 100mm allowing sufficient passage for your IT / telephony cabling and an underfloor power distribution system.

The ceilings are covered by a fully demountable suspended ceiling with a grid and 600mm x 600mm perforated metal ceiling tiles. The ceiling void is estimated to be up to 600mm at its deepest point (excluding dropped beam locations).

All walls plastered with a painted finish, which is in accordance with industry standards.

Doors, Frames & Skirting
Skirting is formed of 100mm veneer. Doors are solid core, timber veneered with veneer frames and stainless steel ironmongery.

Where building services exist, they have been specified, designed and hopefully maintained in order to meet the requirements of building users. Design criteria are established prior to installation of the systems to identify the parameters that they will operate to.

External Conditions
The internal conditions indicated below are maintained when the following ambient conditions prevail:

Winter -4ºC dry bulb 10% saturated
Summer 29ºC dry bulb 20ºC wet bulb

Assumed Internal Conditions
Unless otherwise stated, all internal design temperatures are maintained within the range ±2ºC of figures stated:

Winter Summer
Offices 21ºC 22ºC
Reception 21ºC 22ºC
Stairs / corridors 18ºC no ambient control
Toilets 18ºC no ambient control

Assumed Air Conditioning Load Allowance
Lighting 12 w/m2
Power 25 w/m2
Occupants 10 w/m2

What this means in practical terms is that the air conditioning system in this property will cool the building to 22ºC on a day when it is 29ºC outdoors. This will vary from building to building depending on the design criteria and the geographic location of the building.

The system is not designed to cool a building to less than 22ºC on the hottest days. If the outdoor temperature exceeds 29ºC the building or certain areas of the building may not be able to be cooled as low as 22ºC. Temperatures and humidity may exceed these values for several days at a time during hot spells. These hot spells occur relatively infrequently, less than 2.5% throughout the year, however global temperatures are widely reported to be increasing and as such these spells are likely to increase.

During periods of cold weather, the system is designed to maintain a temperature of 21ºC. If the outdoor temperature drops to below -4ºC the building or certain areas of the building may not be able to be heated as high as 21ºC. There are reasons why building services are not designed to meet the most extreme conditions. Largely it is due to cost, however as extreme conditions account for only 2.5% of the year, under ‘normal’ conditions the services would be greatly oversized and would therefore waste energy. Oversized systems are also poor at controlling humidity.

Mechanical Services
The heating and cooling system within the property is commonly referred to as a Variable Air Volume (VAV) system. In practical terms, the heating, cooling and ventilation are all distributed by central plant, consisting of chillers, boilers and air handling units which serve all floors via the mechanical riser. The Variable Air Volume System (VAV) units are located within the ceiling void above the line of the suspended ceiling.

Public Health Services
The following public health provisions are assumed to apply within the property:

The water storage has been designed to provide 25 litres per person
Hot water will be distributed at 55oC
Cold water storage temperature is less than 20ºC
Hot water storage temperature is a minimum of 60ºC
Hot water distribution temperature is 55ºC
Hot water at accessible WC basins is 41ºC
Rainwater collection and storm water drainage system complies with BSEN12056 Part 3 CAT 2
Building fabric to withstand 100mm / hour storm

Electrical Services
The incoming supply to the building is taken from the one metered 630 amp three phase and neutral low voltage electrical supply serving the office floors and mechanical plants. The electrical provider is Western Power Distribution.

As previously advised, a raised access floor has been installed throughout the floors with a floor void depth of 100mm. The raised access floor provides a very flexible solution to enable the installation of recessed floor boxes throughout complete with all power and data cabling concealed within the floor void.

Lighting – Design Criteria
Lux levels are a measure of the level of lighting in a building or area of a building. The following lighting design criteria have been assumed for the property:

Office areas 450 lux at desk level
Corridor / WC areas 150 lux at desk level
Reception 200 lux at desk level
Plant rooms 100 lux at desk level

Emergency Lighting
Emergency lighting is currently installed to suit the current layout.

Fire Alarm System
There is currently a conventional zone addressable automatic fire detection system. Each detection zone is connected to the main fire alarm panel. The system will need to be adapted to suit the new layout.

There is 1 no. 9 person passenger lift.

The property includes an intruder alarm system comprising control panels, keypads, presence detectors and door contacts. The main entrance has a keypad. The CCTV system installed is dated and requires replacement. The access control comprises control panels, access control devices and emergency buttons. The access control system could be adapted to suit the new layout.

Design Criteria
Property literature advises that the building has been designed to the following occupancy levels:

General occupancy 1 person per 10m2
Lifts 1 no.
WC / bathrooms 1 person per 8m2

We have already identified the limiting factor of occupation with regards to fresh air ventilation, however for completeness this is included again below:

1,982m2 (21,331 sq ft) / 10 (1 person per 10m2) = 192 persons
192 persons x 12 l/s (fresh air coming into the property) = 2,304 l/s total
2,304 l/s (total) / 10 l/s (statutory minimum) = 230 persons

The limiting factor of occupation is the emergency escape door / staircase widths which limits occupation to 95 persons to each upper floor.

260 persons at 10 litres per second at the minimum fresh air setting in extreme weathers
275 male and female combined
95 persons for upper floors

WC / Bathrooms
The current number of WCs allows for an occupancy of:
1,982m2 (21,331 sq ft) / 8 (1 person per 8m2) = 275 persons including DDA

Emergency Escape Door / Staircase Widths
Approved document Part B of the Building Regulations lists the requirement for buildings to be ‘designed and constructed so that there are appropriate provisions for the early warning of fire, and appropriate means of escape in case of fire from the building to a place of safety outside the building capable of being safely and effectively used at all material times’.

In summary the limiting factors of occupation are:

Fresh air ventilation 260 persons
WC / bathrooms 275 persons
Means of escape 95 persons for upper floors


21,331 sq ft
Letting Agents