(Total No of Pages — 08)

Policy No 09/2020

Tele : 23019646 E2 Works (PPC) Sub Dte Dte of Works, E-in-C's Branch Integrated HQ of MoD (Army) Kashmir House, Rajaji Marg, New Delhi — 110011.

A/95533/SoA/HR/Pol/E2W (PPC) 27 Oct 2020

List 'A' and 'B'

GUIDELINES FOR PLANNING OF MULTI-STOREYED/ HIGH RISE BUILDINGS

1. Defence infrastructure development is planned on the basis of operational, functional, training and administrative requirements of Defence Services. The planning of layout and design of buildings is based on requirements projected by various formations/ units/ users and brought out in the Board Proceedings, apart from engineering and architectural considerations. An efficient layout/ design would also optimise utilisation of land apart from primary considerations stated above.

2. In order to achieve optimum utilisation of limited/ scarce land resources the Ministry has time and again emphasised multi-storeyed construction. Paras 1.15 and 1.16 of Scales of Accommodation (SoA) for Defence Services 2009 also contain certain provisions for the same. Though multi-storeyed buildings have been constructed in the past by MES, the present trend and long-term vision is to plan high rise buildings especially in metros/ locations like Mumbai, Delhi etc. Some of the projects under planning are slated for configuration up to G+65 storeys.

3. National Building Code (NBC) published by the Bureau of Indian Standards gives out guidelines for planning of buildings and contains provision for various factors to be considered while planning of multi-storeyed buildings.

4. The following important points shall also be considered and duly factored while planning multi-storeyed buildings apart from regular planning parameters: -

(a) Clearance of Local Municipal Authority. The provisions of "The Government Buildings Act", as given in Para 327 of RMES will be complied with by the MES. In addition to the above as per Part 2 (Administration), Section 3 (11.1.3) of NBC 2016, "Specific approvals shall be obtained from Airports Authority of India, Ministry of Environment, Forest and Climate Change, Fire Services Department, Pollution Control Board, Designated Authorities under Factories Act/ Cinema Regulation Act, Urban Arts Commission, Designated Coastal Regulation Zone Authority, Archaeological Survey of India, Heritage Committee and any such other authority as may be applicable. Fire clearance for building drawings and layout will be obtained as per local byelaws/ rules/ regulations from respective

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authorities, as applicable in each case and in consonance with Part 4 of the Code — "Fire and Life Safety".

(b) Open Spaces & Floor Space Index. For sites within Cantonments/ Military Stations, mandatory open space norms as per NBC and Local Byelaws to be followed. Community open spaces to be provided as per Para 5.0 Part 3 of NBC 2016. For independent pockets not part of Cantonment/ Military Area, Floor Space Index/ Floor Area Ratio norms shall be applicable as per Local Byelaws.

(c) Floor to Floor Height of Individual Floors. The floor-to-floor height of a building is a function of required ceiling height, depth of structural floor system & material and vertical space required for Mechanical, Electrical and Plumbing (MEP) distribution networks. It may vary from 3.2m to 4.8m depending upon type of building.

(d) Structural Considerations.

(i) Structural Systems. The overall building cost and the architecture of a high rise building depends predominantly on its structural system. The high rise buildings are dynamically sensitive to lateral loads and hence the structural system of such buildings are designed to resist the lateral loads, especially wind load or seismic loads. Such buildings shall be governed by various aspects as given below: -

(aa) Elevation.

(aaa) Height Limit for Structural System. Based on lateral loads the height for various structural systems in different seismic Zones shall be as per Table 1 of IS 16700: 2017.

(aab) Slenderness Ratio. The height to base ratio shall be as per Table 2 of IS 16700: 2017.

(ab) Plan.

(aba) Geometry. Shall preferably be rectangular/ square or elliptical / circular.

(abb) Aspect Ratio. The length/ breadth ratio should not be greater than 5.0. In case of 'L' shaped building each arm shall be treated as a separate entity.

(ac) Floor System.

(aca) Material. Floor plate shall be cast in situ only.

(acb) Openings. Shall not be permitted along edges unless perimeter members are shown to have stability and adequate strength. Maximum area of opening in a floor plan

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shall not exceed 30% of plan area. The minimum width of floor slab along any section after deducting of openings shall not be less than 5m and the minimum width of the slab beyond an opening to edge of slab shall not be less than 2m.

(ad) Materials.

(ada) Concrete. Minimum M-30 grade and Maximum M-70 grade.

(adb) Steel. Minimum grade of reinforcement steel shall be Fe 500 (D). No lapping of bars is allowed for diameter of bars greater than 16mm, mechanical couplers as per IS 16172 shall be used.

(ae) Special Requirement. For buildings with single/ multiple towers backstay may be required as per Clause 8.1.3.3 of IS 16700 : 2017.

(af) Structural Wall System. Thickness of structural wall shall not be less than 160 mm or h/20 whichever is larger. Openings in structural wall shall meet the conditions given in Clause 8.5.2 of IS 16700 : 2017.

(ag) Foundation.

(aga) Geotechnical Investigation. Geotechnical Investigation besides normal investigation, potential analysis and estimation of soil spring constants along with modulus of subgrade reaction shall be done. Boreholes shall be spaced at 20m to 25m, with minimum of four boreholes per tower. The depth of boreholes should be at least 1.5 times of estimated width of foundation in soil and 30m in rock.

(agb) Depth. Embedded depth shall be at least 1/15 of height of building for raft foundation and 1/20 of height of building for pile and piled raft foundation (excluding pile length).

(ah) Non-Structural Elements. These shall conform to existing national standards besides guidelines laid down in Clause 10.1 of IS 16700:2017.

(ai) Monitoring of Deformations.

(aha) Earthquake Shaking. Tall Buildings exceeding 150m in Seismic Zone III and IV as also all tall buildings in Zone V shall be instrumented with tri-axial accelerometers.

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(ahb) Wind Oscillations. Buildings greater than 150m shall have anemometers and accelerometers on top of buildings.

(ahc) Foundation Settlement and Pressure Measurement. Permanent settlement markers at corners and centre be provided at raft top level.

(e) Wind Effect. For High Rise and Tall Buildings, wind analysis shall be carried out to evaluate the impact of wind movement and natural flow changes because of the new building proposed to be erected. Strategies may include application of cross-ventilation and thermal comfort, factoring prevalent wind patterns, seasonality, stack effect and other principles.

(f)

Provision of Core Area.

(i) The core of High Rise and Tall Buildings comprises of common circulation elements such as lifts, staircases, fire staircases, horizontal circulation corridors, lift lobbies & shafts (electrical, fire-fighting and water supply & communication shaft etc).

(ii) The core area required depends upon type of accommodation, height of building and plinth area. It varies with the number of staircases, lifts, width of corridor and additional mandatory spaces required in a building. Further it also varies as per site conditions, architectural design, climate and geological location of station and any other relevant factor. Provisions in NBC 2016 do not define numerical values for core area. It is generally noted that percentage of core area with respect to the respective floor plate area falls in the range of 20% to 30% for buildings up to 15 floors and 30% to 40% for buildings beyond 15 floors. It is important that core areas are distributed in such a manner to achieve economy in planning and design. As the height of building increases, core and structural elements tend to expand, to satisfy requirements of vertical circulation and resistance to lateral loads. The enhanced areas in buildings more than 15 floors are due to requirement of additional lifts, service floor, refugee areas etc. Where Local Byelaws require additional area for wider staircases, fire escape, circulation areas etc, the core area has to be suitably increased to meet such requirements.

(g) Accesses and Circulation. The layout and design of spaces for horizontal and vertical movement may be planned suitably by adopting following guidelines: -

(i) Provision for Means of Access. The approach to building and open spaces on all sides shall be of minimum 6m width. The said open space shall be kept free of obstructions and shall be motorable. Main entrances to the premises shall be of adequate width to allow easy access to the fire engine and in no case it shall measure less than 5m. If archway is provided over main entrance bottom of archway shall not be at a height less than 4m. For multi-storeyed group housing on single plot, approach

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(ii) Exit Requirements. Exit requirements shall be as per Para 4.4 of NBC 2016 Vol-1. Basements shall have at least two exits.

(iii) Lifts. As per SOA 2009 Table 55.1 above 10 storey Married accommodation, 2x8 passenger lifts and 1x13 passenger lift are authorized, while requirements of lifts for buildings above 12 storey may have to be planned as per provision of NBC. The lifts (for passenger, luggage, fireman etc) to be provisioned shall meet quantity and qualities of services as per NBC 2016 Part 8 Section 5A & IS 14665.

(h) Fire Protection. Buildings shall be planned, designed and constructed to ensure fire safety and this shall be done in accordance with the provisions laid down in National Building Code of India or local Municipal authority whichever is stringent. The entire scheme must be got approved from the CFEES at conceptual stage ie before submission of the AEs and the items catered in the AEs should be in accordance with the CFEES report. For residential occupancies above 120m in height and other occupancies above 60m in height, the sprinklers shall be fed from the main and an alternate / standby riser with suitable isolation valves (Para E-6 Annexure E to Part 4 of NBC 2016 refers).

The following fire safety measures as per NBC 2016 will be considered during planning: -

(i) Unhindered means of access.

(ii) Compartmentalisation.

(iii) Automatic fire detection and alarm system/ manually operated electrical fire alarm system.

(iv) Public address system.

(v) Illuminated exit way marking signs.

(vi) Alternate source of electric supply.

(vii) Fire lift with fireman switch.

(viii) Underground / overhead water static tanks.

(ix) Wet riser/ down corner system.

(x) Automatic Sprinkler system.

(xi) Fire Hose Reels.

(xii) Fire Points (Fire extinguishers to be procured and maintained by users).

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(xii) Fire Points (Fire extinguishers to be procured and maintained by users).

(k) Alternate Source of Electric Supply (DG Supply). A stand by electric generator shall be installed to supply power to staircase and corridor lighting circuits, lifts, fire detection system, fire pumps, pressurization fans and blowers, exit signs, smoke extraction system, in case of failure of normal electric supply. The generator shall be capable of taking starting current of all the machines and circuits stated above simultaneously.

(I) Lightning Protection.

(i) Lightning Protection Level (LPL). Lightning protection is divided into four levels (LPL Ito IV). LPL I provides the maximum protection and is expensive, whereas LPL IV provides the least protection and is less expensive. Recommended LPL for typical buildings is as under for guidance.

Ser No Applications LPL

(i) Computer data centres, Military applications, High rise hospitals, Essential services such as Telecom

I

(ii) Low rise hospitals, Fuel retail outlets/ Gas stations/ Compressor stations and similar installations

II

(iii) School, Banks, Residential buildings, Temples, Churches, Mosques, Community halls etc

III / IV

(ii) Lightning Protection System (LPS). The type and location of an LPS should be carefully considered in the initial design of a new structure thereby enabling maximum advantage to be taken of the electricity conductive part of the structure. Soil resistivity and the nature of the earth should be considered at the earliest possible stage of a project.

(iii) Air Termination System. Air Termination system is a part of an external LPS using metallic elements such as rods, mesh conductors or catenary wires intended to intercept lightning flashes. On structures taller than 60m, flashes to the side may occur, especially to point, corners and edges of surfaces. In general, the risk due to these flashes is low, but electrical and electronic equipment on walls or outside structures may be destroyed even by lightning flashes with low current peak values. An air-termination system shall be installed to protect the upper part of tall structures (that is, typically the topmost 20% of the height of the structure as far as this part exceeds 60m in height) and the equipment installed on it. The rules for positioning the air-termination systems on these upper parts of a structures shall meet at least the requirements for LPL IV with emphasis

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on the location of air-termination devices on corners, edges, and significant protrusions (such as balconies, viewing platforms etc (Part 8 Building Services Section 2 Electrical and Allied Installations of NBC 2016 refers).

(m) Service Floor. Where the height of the building exceeds 150m to 175m, the service floor is required to have fire water static storage and pumps at 160m to 180m and thereafter at intermediate floors at higher levels. The fire pump room at such level shall have dedicated connectivity through passageway from the firefighting shaft (Annex E Para E6 Part 4 Fire and Life Safety NBC 2016 refers).

5. Green Building Certification. As per Policy No 23/2017 of E-in-C's Branch minimum GRIHA 3-star rating certification from Government approved rating agency shall be obtained for Married/ OTM Accommodation Projects costing more than 20 crore. Provision of Green Building Norms for GRIHA 3-star rating will be included in the BPs/ DPR with due recommendations.

6. Miscellaneous.

(a) As per NBC 2016 railing height shall be 1.1/1.2m as given in Table 35 (Page 73, Part 6 Structural Design, section 8, Glass and Glazing). Wherever there is difference between NBC 2016 and Local Byelaws, stringent of the two norms may be followed.

(b) Provision for barrier free access as per NBC 2016 (Vol-I) Part 3, Annex 'B' (Page No 61) and the Local Building Byelaws shall be provided.

(c) Provision for connecting piped gas may be provided, suitable pipe shafts / entry points shall be designed. Government instructions issued vide Gol, MoD letter No B/87898/Plg (Lands)/2016/95/S0 (II)/D (Lands) dated 01 Mar 17 (copy enclosed as Annexure II) will be followed in this regard. No permanent / temporary structure shall be erected on the ground along the paths where gas pipeline exists underground.

(d) Permanent finishes/stone finishes shall be provided in lift lobby because of its frequent use. External acrylic/ apex paint or any other maintenance free permanent finish is recommended on the external surfaces.

7. Automation. Utilisation of Building Management System (BMS) and automation of water and power supply system through SCADA may also be considered. Intelligent design features and systems may also be considered in planning for conservation of water, energy etc.

8. The provisions included in these guidelines are not necessarily mandatory for all multi-storeyed buildings. Each project/ building shall have provisions as per its specific requirement and shall be planned and designed accordingly. These guidelines may be suitably considered for each building/ project/ work, after due deliberations and included in the findings and recommendations by Board of Officers as per actual requirements.

he provisions, scales, areas, facilities, furniture, services shall be in consonance YWith Scales of Accommodation for Defence Services. Other necessary functional

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9. The guidelines contained herein are neither exhaustive nor complete and are to be read in conjunction with other instructions on the subject as well as requirements stipulated by relevant codal provisions, latest NBC guidelines, other statutory/ mandatory regulations etc.

10. For information and necessary action please.

Mohit Nautiyal) Brig DDG (PPC & Est) For E-in-C

Copy to: -

QMG's Branch/ DG LWE Dte

IHQ of MoD (Navy) / Dte of Works

Air HQ / Dte of AF Works

HQ IDS / Works Dte

HQ SFC

Coast Guard HQ

QMG's Branch / ADG TE

HQ CME Pune

Faculty of Construction Management, CME Pune

Internal

HQ DG MAP

All Sub Dtes of Works Dte

Automation Cell - For uploading on MES website in open domain.

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