raise flooring_floor load

Engineering IT Infrastructurewww.Capitoline.eu

Introduction toData Centre Design

Barry Elliott BSc RCDD MBA CEng

Raised floors Raised floors

October 09


Raised floor design issues• Load bearing capacity• Height• Finish/décor• Plan access ramps• Plan air grill and damper location• Seal all the system for air con efficiency and

fire spread reduction• Earth bond all the metalwork• Good and suitable finish to original floor

Engineering IT Infrastructure

600 and 610 mm floor tiles


Minimum floor loading capacity Floor loading capacity in the computer room shall be sufficient to bear both the distributed and concentrated load of the installed equipment with associated cabling and media. The minimum distributed floor loading capacity shall be 7.2 kPA. The recommended distributed floor loading capacity is 12 kPA.

Minimum ceiling height: The minimum height in the computer room shall be 2.6 m (8.5 ft) from the finished floor to any obstruction such as sprinklers, lighting fixtures, or cameras. Cooling requirements or racks/cabinets taller than 2.13 m (7 ft) may dictate higher ceiling heights. A minimum of 460 mm (18 in) clearance shall be maintained from water sprinkler heads.

TIA 942 location recommendations are:


TIA 942

Décor. Floors, walls, and ceiling shall be sealed, painted, or constructed of a material to minimize dust. Finishes should be light in color to enhance room lighting. Floors shall have anti-static properties as per IEC 61000-4-2.

Raised floors are based on 600 x 600 mm floor tiles in Europe and 24 x 24 inches in the USA

They sit on pedestals which may be glued or bolted to the floor

Additional strength and stability between pedestals can come from stringers reinforcing the pedestals


Raised floorsThe Property Services Agency (PSA) Method of Building Performance Specification 'Platform Floors (Raised Access Floors)', MOB PF2 PS, became the de facto industry standard in the UK for about 20 years until the recent arrival of the BS EN 12825:2001 specification.

In July 2001 a European Standard EN 12825 Raised access floors,was approved by CEN as a voluntary specification for private projects and mandatory for public projects. It is anticipated that this standard will become mandatory for all projects across the member states of the EU within 5 years of approval.


The minimum distributed floor loading capacity shall be 7.2 kPA. The recommended distributed floor loading capacity is 12 kPA. TIA 942

Raised floors - loading


Floor heights


What height?

• 450 – 600 mm, IBM• 450 min, 600 ideal, SUN• 300 – 600 mm, BS EN 12825• 300 mm min, TIA 569• Raised floor min height 460 mm, BICSI


A deeper floor evens out the airpressure and distribution

APC


Where will the cables go?

• Under floor. – Out of sight, out of mind– Will interfere with air flow

• Under the ceiling– Less aesthetically pleasing– Easier to manage and change


If cables must go underneath…..

Seal cable entries under cabinets e.g with brush strips


This kind of cabling negates the plenum zone effectiveness at air distribution


Power, data, earth system and smoke detection in 400 mm floor space


Requirements

• The floor base must be clean, sealed and even

• The plenum zone created must be sealed, free of dust and with no cable or pipe work entrances that aren’t also sealed


The reasons for pressure sealing the plenum area are;

• Chilled air conditioned air will be able to escape through poorly finished floor tiles and service penetrations, leading to;o More electricity consumed to replace that airo An inability to deliver the volume of chilled air required at the floor ventso A variation in air pressure across the floor leading to an inability to deliver chilled air

at the air vents• Unsealed service penetrations (cables/pipes etc) into the plenum area are a

fire risk and will allow the spread of fire and smoke into or out of the computer room (Building Regs, part B)

• Gaseous fire suppression systems rely on lowering the level of oxygen available to fires and depend upon a sealed area to work in to prevent oxygen from re-supplying the fire. BS ISO 14520 P1: 2000(E), Gaseous fire-extinguishing systems. Physical properties and system design. General requirements, requires a pressure test every twelve months

• Vermin


National Building Specification

The National Building Specification is published by NBS Services (part of RIBA Enterprises Ltd) is a library of clauses that is available to specifiers for selection and editing to produce project specifications using packages such as NBS Specification Manager.

Clause K41 covers raised access flooring and this forms the basis of the vast bulk of raised access flooring specifications in the UK.


K41


More K41350 PERIMETERS:Ensure that the installed system has sufficient lateral stability to enable it to be independent of abutting elements.Provide a 10mm expansion gap at all abutments and fill with a resilient closed cell filler before fixing skirtings, cover strips, etc.


The floor is an essential part of the cooling system

• “Poor airflow management takes 50% or more of the CRAC capacity” Pacific Gas and Electricity

• “60% of the cooled air in a typical data centre does not flow to where it is needed” (UpTime Institute)

• “70% of cooling air is wasted and bypasses back to return system” Mazzetti Associates


Ramps

· Ramps and steps: Construct to approved details to achieve performance requirements specified for the associated raised access floor.

· Balustrades: Ensure compliance with the structural and safety requirements of BS 6180.


Ramps: The Building Regs 2000 Part M. Access for disabled

i.e at 1:12, a 450 mm floor needs at least a 5.4 m ramp


Build the Signal Reference Grid before fitting the floor tiles


Grounding - earthing

Every sixth* metallic raised floor pedestal needs to be bonded to the Signal Reference Grid, SRG. This helps to bleed off static charges built up from the raised floor system.

*EN 50174-2 suggest every 2 or 3 pedestals earthed with a 10 sq mm wire


Beware zinc whiskers

• Zinc whiskers grow on metal stringers or off the bottom and sides of floor tiles that have a zinc electroplated-passivation coating on the sheet-metal pan.

• Specify hot-dipped galvanized (HDG) or electroplated zinc

raise flooring_floor load

Documents

raised floor

floor tiles engineering

floor space engineering

floor base

infrastructure tia

air distribution engineering

infrastructure requirements

pedestals engineering