Access for Maintenence - Metric Handbook

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45 Access for maintenanceCI/Sfb: (75)

UDC: 624.059

Uniclass: MX22

KEY POINTS:

Health and safety considerations are of the highest priority Design that does not take maintenance into account isunacceptable

Contents

1 Method and frequency of cleaning

2 Access

3 Internal access

4 External access

5 Roof suspension systems

6 Bibliography

1 METHOD AND FREQUENCY OF CLEANING

1.01 Method

The methods by which windows and facades are to be regularly

cleaned and maintained must be considered at an early stage of

design, and the necessary equipment incorporated into the struc-

ture. Recent incidents and subsequent legislative measures

reinforce this, and failure to ensure proper provision may result

in very expensive remedial work.

Regular washing with cold or warm water (sometimes with a

mild detergent) is normally adequate, applied either by swab with

chamois leather to dry and scrim to polish; or by squeegee, which is

much quicker over large areas and when used from cradles.

Between 400 m2 and 500 m2 in eight hours is average, using a

squeegee in ideal conditions.

1.02 Frequency

Table I shows some recommendations for frequency of washing

according to locality, and Table II gives frequency of washing

particular building types in non-industrial areas. For industrial

areas and cities the interval between cleans should be halved.

2 ACCESS

2.01 Internal or external access?

Type of access is decided by:

Method and frequency of cleaning Capital and running costs Whether cleaned by tenants or professional window cleaners Safety requirements Appearance of equipment when not in use.A general guide to selecting external types of access is shown in45.1. When selecting internal types of access, take into account

possible problems:

Type of window (especially high-rise housing) Method of cleaning adjacent exterior cladding Freak draughts and disruption to air-conditioning when opening

windows

Disruption to furniture and activities; possible damage toproperty

Relative cost of providing opening windows (for cleaning frominside) against cost of cradle (for cleaning from outside)

Safety (beware cleaners, especially tenants, having to lean out toclean adjacent fixed lights).

Cleaning the internal glass face is usually no problem unless

inaccessible.

Often two separate contractors are given the work of cleaning

the inside and outside faces. Cleaning the outside from the outside

will usually give better results, and can effect long-term savings

over the extra cost of providing opening windows to allow cleaning

from inside.Table I Recommended frequency of cleaning per year

Location Groundfloor facing

street

Otherwindows

Rooflights

London postal area and smoky

industrial areas of large cities

16 8 2

Semi-industrial towns 12 6 2Non-industrial towns 8 4 1

Table II Recommendations for frequency of washing of particular building types

Type of building Side windows Rooflights

Offices Every 3 months Every 12 monthsPublic offices, banks, etc 2 weeks 3 monthsShops Outside every week Inside

every 2 weeks6 months

Shops (in main streets) Outside daily Inside everyweek

3 months

Hospitals 3 months 6 months

Schools 34 months 12 monthsHotels (first class) 2 weeks 3 monthsFactories (precision) 4 weeks 3 monthsFactories (heavy work) 2 months 6 monthsDomestic (by contract) 46 weeks

Ground-floor windows facing streets should be cleaned at twice this frequency 45.1 Chart for selecting system for external access

45-1


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3 INTERNAL ACCESS

3.01 Ergonomics

Human dimensions related to window cleaning are shown in 45.2

to45.5. andTable III.

3.02 Types of window

To avoid accidents with small children, all opening windows,

except possibly those less than 1.5 m above the ground outside,

should now be fitted with devices to prevent them normally open-

ing to leave a gap more than about 100 mm. This device has to be

removeable for cleaning purposes, but the method should

obviously be child proof. When any degree of leaning-out to

clean windows is involved, a safety harness linked to an internal

anchorage must be used. Two such examples are shown in 45.6.

Side-hung casements should have offset pivot hinges to giveminimum 100mm gap, set well forward of the frame which

should not be fixed more than 100 mm in from the external face.

Consider using Continental-type inward-opening casements

which solve most window-cleaning problems.

Double-opening windows have both side hinges and hopperhinges allowing for easy cleaning and safety.

Hopper windows opening inwards must be low and narrow foreasy cleaning. If high and large, they can be dangerous.

Vertical and horizontal sliding sash windows should not be usedfor internal cleaning.

Horizontal and vertical pivot windows are satisfactory for inter-nal cleaning if they can be fully reversed and securely fixed withlocking bolts both when reversed for cleaning and open nor-

mally for ventilation.

Sliding projecting windows can be dangerous for internal accesscleaning unless maximum depth is 750mm, but even then

cleaning can be hazardous.

4 EXTERNAL ACCESS

4.01 Manual cleaning: access from ground

Type of access can be initially assessed from 45.1. Manual clean-

ing methods with access from the ground include:

On foot: maximum window height 1.8 m providing there are noawkward projections.

Single part ladder: up to 3 m, but awkward with long horizontalwindows (use travelling ladders see para 4.02. Long-handled

squeegee can sometimes be used instead.

45.2 Exterior reach to adjacent fixed light through opening light.

Shaded area is average acceptable size for ease of cleaning

45.3 Interior reach to fixed, reversible or pivot window

45.4 Reach becomes less over bench or worktop

45.5 Dimensions of fixed light heights and guard rails for

domestic buildings

45.6 Two situations where cleaning access is from the inside, but

when a properly anchored safety harness should be used

45-2 Access for maintenance


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Table III Access to external faces from the inside Note: shaded area indicates glass face

Good Satisfactory Bad

Casement

(1) Inward opening (2) Outward opening with extending hinges (3) Outward opening

Double opening hopper

(4) (5) Inward opening (6) (7) Outward opening

Vertical slide

(8) (9)

Horizontal slide

(10) Top corner reach possible (see 45.2) (11) Corner reach not possible

Horizontal pivot

(12) Completely reversible (13) Not completely reversible and too high

(see 3)

Vertical pivot

(14) Completely reversible (15) Not reversible but at correct height

(see 45.3)

(16) Not reversible and too high (see 44.3)

(Continued)

Access for maintenance 45-3


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Ladders over 3 m must be secured. Maximum 9 m, safe inclina-tion 83. Securing can be with mechanical anchorage, as to the

ground, 45.7. The top of the ladder can be restrained using

proprietary D wheels, 45.8a. These rubber wheels with hol-

lows between the rib and the hub are stiff enough to stay round,

45.8b, when the ladder top to which they are fixed is moved up

or down the wall. When the ladder is in use, the wheel is pressedagainst the wall and becomes the D-shape that holds it securely,

45.8c.

Mechanical ladder on mobile chassis. Can be either freestandingor leant against a wall. More rigid than simple ladders but still

only gives access to limited areas.

Single stepladder in the form of a mobile trestle. Maximumheight is 5.4 m.

Lightweight portable scaffolding. Height is maximum three timesleast base dimension unless weighted, tied back to building, or

outriggers fitted. Special scaffolds can be made to suit building

design. Provides safe, rigid platform leaving both hands free.

Table III (Continued)

Good Satisfactory Bad

Top hung

(17) Top-hung opening in (18) Top-hung opening out is impossible to clean

Fixed adjacent

(19) Corner reach possible (20) Corner reach impossible

(21) Centre reach possible (22) Centre reach impossible

Access to internal faces

Double glazing

(23) Fully reversible pivot (24) Inward opening casement (25) Top-hung opening. Too large and distorts

when held by corner

45.7 Ladder with feet supported and fixed in natural ground

45.8 Ladder with top restraint (Ladderfix Ltd). a D wheels fitted

to ladder.b D wheel able to roll. c D wheel under load



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Zip-up staging in light, hinged aluminum alloy sections each2.14 m high 1.6m long 1.35m wide. Height is maximum four

times least base dimension, but outriggers and restraint can increase

this ratio. Again, variations are possible to suit building design.

Mobile folding and telescopic platforms, only for use as sec-ondary access for difficult areas. Generally of fixed height

between 12 m and 15 m.

4.02 Manual cleaning using permanent access

There are five main possibilities:

Balconies: but only if all windows can be reached, otherwisesome other forms of access will be needed.

Sills and ledges: if continuous, more useful to a professionalwindow cleaner than a balcony. Construction Regulations 1966

suggest 630mm as minimum width, but some cleaners will

accept 300 to 500 mm width. A ledge from which a fall of 2 m

or more is possible must be provided with either a guard rail or a

continuous safety harness anchorage, as in 45.9. Ledges requir-

ing the operative to clip, unclip or reclip his safety harness while

on the ledge are not acceptable.

Catwalks: mainly for lateral movement. Must be level and non-slip. Maximum gradient of 20. with regularly spaced steppinglaths for sloping roofs; above 20 needs steps. Internal catwalks

need 2 to 2.15 m headroom. Minimum footing width 630mm

(870 mm if materials put on gangway): guard rails between

900mm and 1150 mm above platform when more than 2 m

above ground; toe boards 150 mm deep with maximum distance

of 750 mm between the board and lowest guard rail.

Fixed ladders: use steps up to 70, rungs over 70 pitch, 45.10. and45.11. Vertical ladders not recommended, but where necessarily

used must be caged. Use landings every 6 m height positioned to

break fall, or use metal mesh safety cage over the ladder.

Travelling ladders: with top and bottom fixings on continuousrail or channel to allow ladder to slide along and round the

facade. Useful for long bands of glazing up to 4.5 m high; can

be fixed at almost any angle.

5 ROOF SUSPENSION SYSTEMS

5.01 Temporary systems

These are usually hired and erected and dismantled each time.

There are two systems:

Counterweighted system as shown in45.12. Rather unwieldy andlimited; roof structure and parapet must be capable of taking load.

Fixed davits as shownin 45.13. Same problems as thecounterweightsystem but safer, although horizontal traverse is more difficult.

There are also a few proprietary portable gantry systems.

5.02 Permanent systems: trolley units

A permanent system is usually desirable and for frequent cleaning

soon covers the extra initial cost; but unless carefully designed and

integrated with the structure and facade it can look very unsightly.

a

b

45.9 A continuous wire cable with harness-clip that rides through the anchor fixings (Latchways plc). a Fixing to a wall. b In use



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45.10 Fixed ladder leading to interior catwalk

45.11 Recommended dimensions for fixed ladders and landings,

based on Construction Regulations 1966 (with additional

information from Industrial Data Sheet 53) (Australian

Department of Labour).a up to 70

xhead clearance, min 1050 mm for 60 slope, 950 mm for 70slope

z steps, minimum width 100 mm, 200 to 250 mm rise flight width

450 to 750mm.b over 70 with cage

45.13 Fixed davits on a roof with parapet

45.14 Hand-operated roof trolley travelling on twin track. The

boom can be lowered to the horizontal to deal with projections on

the face of the building

45.12 Cradle using counterweight system

To balance CTWO

for safety CT should not be less than three times WO 45.15 Bosuns chair in performed plastic



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In all cases roof structure and finishes must be able to carry the

imposed loads. There are two elements to consider: the roof trolley

system and the suspended chair or cradle (see para5.03) There are

two trolley systems:

Manual roof trolley consisting of a continuous rail, often RSJ,positioned about 450 mm in front of the wall face, to which the

cradle is attached by ropes and castors. The most common is a

pair of continuous rails, fixed to the roof about 750 mm apart, on

which runs a cantilevered trolley,45.14.

Powered roof trolley is the most efficient and safest and isessential for heights of over 45 m. It is also the most expensive,

but can be relatively cheap for large buildings. It must be

considered at the very earliest design stages. The general prin-

ciple is the same as the manual trolley except that the unit is

powered. Power supply needed is 440 V three-phase.

5.03 Suspended units

There are two basic types: chairs and cradles:

Bosuns chair, 45.15, extensively used for awkward areas andalways used with manual gantries. A modern version is the

facing bicycle, with pedals to work the winch.

Manually operated cradle. A typical standard timber cradle isshown in45.16.Not recommended for heights over 30 m.

Power-operated cradle. Sizes range from 1.8 to 9 m width;materials can be steel, aluminium or GRP.

In all cases some form of manual or mechanical chair or cradle

restraint, and of independent safety harness for the occupants, must

be provided. The only method to provide continuous restraint is a

mullion guide,45.17.

6 BIBLIOGRAPHY

General

The Construction (Health, Safety and Welfare) Regulations 1996

BS 5974: 1990, Code of practice for temporarily installed sus-

pended scaffolds and access equipment

BS 6037: 1990, Code of practice for permanently installed sus-pended access equipment

BS 8213: Part 1: 1991, Code of practice for safety in use and

during cleaning of windows and doors

SI 1998/2307 Lifting Operations and Lifting Equipment

Regulations 1998

45.16 Standard timber cradle. a Side elevation. b End elevation.

cPlan

a b c d

45.17 Mullion guides.a Standard mullion. b Roller on guide to prevent lateral movement. c Casters on guide to prevent outward

movement.d Standard roller



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SI 1997/831Lifts Regulations 1997

SI 1999/3242 Management of Health and Safety at Work

Regulations 1999

SI 1998/2306 Provision and Useof Work Equipment Regulations 1998

SI 1999/1148Water Supply (Water Fittings) Regulations 1999

Health and Safety Executive publications

HSG 150Health and safety in construction

GS 42Tower scaffolds

CIS No 5Temporarily suspended access cradles and platforms

GS 31Safe use of ladders, step ladders and trestles


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