I.
Introduction
1.Background
The Commercial Properties Section (CPS) of the Housing Department (HD) proposes to convert an open space in the Chuk Yuen Estate into a multi-storey food court plaza, aiming at generating more revenue to the Department. This proposal states the constraints and problems arisen during the conversion process and provides a detailed design for the proposed food court plaza.
2.Site
Particulars
The site is on the lower ground floor of the Chuk Yuen Estate next to the Community Centre and the commercial complex, with a dimension of 22.7m x 43m (area: 976m2)[1].
II. Building
Plan Approval
Since the site is located in the area belonging to the HD, subject to sections 18(2) and (3) of the Housing Ordinance (Cap. 283), the Housing Authority is empowered to the control and management of its property and thus under s41 of the Buildings Ordinance, the HD is exempted from the requirements set in the Buildings Ordinance. The Housing Authority has the authority to approve the building plans of this proposed conversion project, but it still has to seek advice from various government departments, e.g., the Environmental Protection Department and the Fire Services Department, etc. before commencing the construction work.
III. Site
Constraint
1.Emergency
Vehicular Access (EVA)
According to the Fire Circular Letter no.4/96 PART X, the EVA of the original commercial complex (with 6m wide to permit the efficient manoeurving of fire appliances for rescue and fire fighting purposes) should be kept. Therefore, the new building is proposed to set back to maintain the original EVA which could give access to the major face of the new building and also the F.S. inlet of the existing building. In order to compensate the loss of EVA of the existing building, every floor of the existing building would be connected by a bridge so that in case of fire people in the existing building could reach the main face of the new building to seek help.
2.Relocate
The Trees On The Site
There are 22 trees in the site that should be fallen or relocated to other area. As the site is leased to the Housing Authority, the Housing Authority (owner of the trees) has the responsibility to ensure that no trees are unnecessarily fallen[2] and should try to preserve the trees as many as possible. Therefore, it is suggested that trees on the site should be relocated to other areas in the same estate or to other public housing estates with due care. Before doing so, the Housing Authority might seek advice from the District Lands Officer setting out the reasons why tree felling is considered to be necessary with full information including plans for replanting at least 3 months in advance.
3.Remove
Lamp Posts
The existing five lamp posts sited in the planters are proposed to be removed. Before carrying out this work, the Housing Department should notify the CLP Power Hong Kong Limited to disconnect the electricity supply to them.
4.Lighting
and Ventilation Outlets From Existing Commercial Building
In general, the kitchen areas should provide prescribed windows for natural lighting and ventilation, but since the Hong Kong Housing Authority has its own authority to approve building plan, there is no need to apply exemption to the Buildings Authority.
For the purpose of maximizing the site coverage and minimizing the adverse effect made on the lighting and ventilation to the existing building, the proposed building is separated from the existing commercial complex by 2m. Mechanical lighting of the existing building might be upgraded to maintain the original luminous level if necessary. Besides, the gaseous emission from both the existing restaurants (only on 2/F) and the new restaurants should not give rise to an air pollution problem; otherwise the Environmental Protection Department would charge the owner of the existing restaurants and advise the Director of Food and Environmental Hygiene Department (the Licensing Authority of restaurants) to disapprove the licences of the new restaurants.
In order to avoid air pollution produced by the restaurants, the ventilation outlets from the existing restaurants, which would face the proposed building, are suggested to be grouped together and to face the Nga Chuk Street because there is no building in this direction within 20m. Regarding the new restaurants, similar approach should be adopted by tenants.
5.Identify
The Underground Services Pipes & Manholes
The site contains different kinds of manholes which are connected by many underground services pipes/ducts such as drainage pipes for discharging foul water and rainwater, electrical wires and gas pipes, etc. They should be clearly identified before the design of foundation. In order to avoid any relocation work to these underground services pipeworks and manholes, the foundation would be located with special care[3].
IV. Proposed
Design
The proposed food court plaza will be constructed as a 5 storey building (G/F to 4/F). The G/F is mainly designed for special rooms and not for commercial purpose. On both 1/F and 2/F, there will be a food court consisting of 4 small size food production shops with a shared dining area. On both 3/F and 4/F, there will be a restaurant[4].
A. Licensing Requirements
The licences for restaurant (3rd & 4th Floor) or food factory (1st & 2nd Floor) should be applied by the future tenants. In designing the food court plaza, we have to meet the following basic requirements:
1.Requirements
For Kitchen, Food Preparation Room & Scullery Accommodation
All food rooms including kitchens, food preparation rooms and scullery areas could either be separated or combined in one room. In our design, they are combined in one room which is separated from the rest of the premises by permanently fixed enclosures from floor to structural ceiling. This arrangement allows flexibility for tenants to assign these rooms by themselves in the future.
Besides, there is a minimum area requirement for kitchen and the aggregate area of kitchen, food preparation room and scullery accommodation. The table below shows the requirement of a general restaurant:
Regarding the food factory licence, the aggregate food room area of not less than 6m2 shall be provided in food factories selling take-away cooked food/fast-food.
From the Schedule of Capacity, the
kitchen area (including preparation area/counter) of each food factory is 37.5m2 (150/4),
which fulfils the minimum requirement of 6m2. While in the case of
restaurant, the kitchen area (including preparation area) is 100m2
(26% of gross floor area), which is larger than the minimum requirement of 54 m2 or
21% of GFA.
2.Fire
resisting construction
All kitchens
in the proposed food court plaza are enclosed with walls with 1 hr fire
resistance period (FRP)[5]
and the opening
in the enclosure would be defended by fire resistant
doors having an
FRP of 1/2 hour. Besides, food hatch formed on the enclosure wall of the
kitchen is protected by fire shutter having an FRP of 1/2 hour[6].
Since the
restaurants/food factories are situated in a shopping arcade, protected lobbies are provided
between each door of the kitchen and the escape route or the dining area.
3.Means of
escape
Every floor on
the food court plaza is provided with adequate means of escape. In our design,
there are two exit staircases, which lead directly to a street on G/F and the roof. Apart from
that, the direct and travel distances to the exit routes on every floor fulfil
the statutory requirement[7].
The details of other MOE requirements are shown in the Schedule Of Exit Means
Requirement and Discharge Value Calculation.
4.Sanitary
Facilities
In order to satisfy the licensing requirement, toilets (and disabled ones[8]) are provided on 1-4/F with sufficient sanitary facilities such as watercloset fitments, urinals and lavatory basin. Detail calculation is shown in the Schedule Of Capacity and the Schedule Of Sanitary Fitments Requirement.
5.Drainage
System
Foul water should be discharged to a foul sewer while surface water should be discharged via rainwater pipes to stormwater drains[9]. There would be some new discharging pipeworks connecting the foul sewer and stormwater drains. However, the HD can carry out the alternation works without approval from the Buildings Authority as these works do not involve the alternation of existing manholes[10].
In order to observe the requirement laid
down in the Water Pollution Control Ordinance, the greasy wastewater created by
the restaurant should be treated by grease trap before discharge. Since all
wastewater collected from each restaurant kitchen, basins, sinks and floor
drains should be discharged via a grease trap, it is preferable to install a
grease trap at a lower level than the kitchen floor. In order to save space, a
common grease trap managed by one company is recommended to be installed in a
grease trap room on G/F, about which consent should be obtained from the
Environmental Protection Department. The grease trap would be located beside
the EVA to facilitate the routine clean up activities carried out by the grease
trap waste collection vehicles.
Since the total kitchen area[11] in the proposed food court plaza is 500m2, a grease trap with a retention volume of 7.8 m3 is provided[12].
6.Potable/Flushing
Water Supply
Undoubtedly, flushing water and potable water should be supplied in the proposed building. Therefore, a flushing water tank and a potable water tank would be installed on the roof. Also, a pump room on G/F would be constructed for siting the water pumps.
7.Connection
To Town Gas
In general,
the use of fuel in restaurants is subject to the control by the Fire Services
Department and the Electrical and Mechanical Services Department. From the environmental point
of view, gaseous fuel should be used. Therefore the
proposed food court would be provided with town gas connections. The HD needs
to contact the
Hong Kong and China Gas Company Ltd. for the
installation of Town
Gas connections.
8. Fire
Services Installations
Various fire services should be installed to meet the Fire Services Department requirements. Because the total area of the new building exceeds 230m2, a sprinkler system (with fire alarm system) is provided to cover all parts of the building including staircases, common corridors and toilets. Fire hydrants are installed in the two exit staircases and hose reels are located outside the staircases so that every parts of the building could be reached within 30m. Moreover, F.S. water tank and sprinkler water tank are placed on the roof. The pumps of these systems are placed in the F.S. pump room on G/F. The F.S. inlets and sprinkler inlet are installed outside the staircases on G/F so that the Fire Services Personnel could access them easily.
Other F.S. installations including exit signs, fire detection system and emergency lighting system (with an independent power generator) throughout the entire building and all exit routes would be installed in the food court plaza.
B. Other Design Considerations
1.Facilities
For Persons With Disability
Apart from providing disabled toilets on every floor, the lift in the existing building would be used as an access to the proposed building for persons with disability. The wall surrounding the lift would be demolished and the floor slab of that structure would thus be connected to the proposed building for traffic convenience for the disabled persons. Tactile graphics would be provided in the lift control buttons and the lift control panel would be lowered to 1m above the floor of the lift car. Besides, tactile warning strip and tactile guide path would be installed near the lift zones, ramps and exit staircases.
2.Maintain
An Open Air For The Existing Exit Staircase
In the existing building, there is a circular exit staircase with unprotected opening. Since the proposed building would be within 6m from this staircase, walls with 2 hrs FRP (greater than the FRP required for the wall of staircase i.e. 1 hr) would be constructed to enclose the staircase from 1/F to 4/F. These walls will be 1.5m apart from the opening of the staircase so as to maintain a vertical unobstructed open air, with horizontal area more than 4 m2 [22.6 m (total height of the proposed building) /6m @ 4].
3.Mechanical
Ventilation System
As common areas occupy a large volume in the food court plaza, a centralized air-conditioning system, which could not only save floor space but also not affect the façade outlook, is recommended. This system only covers the common circulation area and the dining area, excluding the kitchens and toilets. It has a control system to stop its operation during fire. On every floor, there is an A/C room for placing the AHU unit connecting the ductworks, while the huge chiller units would be placed on the roof. An independent and separate ventilation system would be provided for the kitchens and toilets.
4.Allocation
Of Special Rooms
These special rooms are located on G/F:
• Transformer room
• M.D.F. room
• Pump room
• F.S. pump room
• F.S. control room
• Switch room
• Grease trap room
• A/C room
In order to cope with the change, we
propose to demolish the existing long ramp occupying much space on G/F. A new ramp
and a new staircase directly linked to the lobby would be provided to maintain
the accessibility for the public.
In order to make better utilization of floor space, A/C room and switch room would be located near the lift shaft from G/F to 4 /F. Consequently, the existing staircase in the main entrance would be relocated nearer to Nga Chuk Street[13].
5.Provide
Mechanical Lighting To The Public Area On Ground Floor
Since the proposed building is only about 9.5 m apart from the Community Centre, extra lighting should be provided to maintain the luminance level of the passage between these two buildings. Ten lamps are suggested to be hanged on the façade of the new building (bottom part of 1/F) in 4m intervals and six lamp posts near the main entrance of the building would be constructed.
V. Technical Site Problems Encountered During
The Course Of Work
1.Hoarding
Before commencing construction works, steel hoarding surrounding the site with a main gate for vehicular access and a covered walkway[14] would be constructed. Because the hoarding would block the EVA during the construction process, a letter should be written to the Fire Services Department to apply for temporary obstruction of EVA.
2.Site
Safety
As the wall
enclosing the lift would be demolished on every floor, there should be some
hoardings with warning notice surrounding the void after the demolition.
Regarding
the scaffolding, double row steel type is recommended because it is more stable
and provides more working space. Besides, dust screen would be provided to
prevent the spread of dust generated from the site works.
For the convenience of delivering materials in the construction site, a tower crane would be installed. Although it is constructed to maximize its coverage, attention should be put to avoid it from crushing into the existing building or exceeding the site boundary.
Since there
is no road to the site, the EVA which is not designed for vehicle in general,
would be used as a road for delivery of building
materials. The contractor
should be required to properly cover the dumper with plastic sheet to prevent
the falling of waste/building materials and to post warning noitice along the
traffic route through contractural clause.
3.Noise
Control
When using powered mechanical equipment for the purpose of carrying out any construction work other than percussive piling at hours of 7 p.m. and 7 a.m., or at any time on a general holiday, a permit should be sought from the Environmental Protection Department[15].
Regarding the piling work, owing to the proximity to the surrounding buildings, a piling permit (for percussive piling) should also be applied to the EPD, which would determine the time schedule for piling work. No piling work should be carried out beyond the set time.
VI. Schedule
Of Work & Construction Cost
The following is a summary of the project details of the proposed food court plaza:
|
Day Of Commence: |
1 July 2001 |
|
Day Of Completion: |
4 Aug 2002 |
|
Construction Period: |
400 Days (13 months) |
|
Estimated Cost: |
$16,896,500 |
Details of the project construction cost and schedule of work are shown in the Schedule Of Rates and Master Working Programme respectively. A specification is also provided for reference.
VII.
Conclusion
The proposed multi-storey food court plaza is economically viable and would generate more revenue to the CPS. Through careful design, the open space in Chuk Yuen Estate would be better utilized and people could then enjoy the diversified mix of food court. As a result, the conversion work can attract more visitors to the existing commercial complex and benefit the public in that district.