stadium seating

SEATING

SIGHTLINES

CONVERSION OF

TERRACING

SEAT TYPES

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-FOOTBALL STADIA

ADVISORY DESIGN

COUNCIL

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SEATING

SIGHTLINES

CONVERSION OF TERRACING

SEAT TYPES

S i

y C o n t r i b u t o r s

Rod Sheard

Ernest Atherden

Tony Sherratt

E d i t o r

Simon Inglis

T e c h n i c a l E d i t o r a n d I l l u s t r a t o r

M aritz Vandenberg

© T h e Fo o t b a l l St a d i a Ad v i s o r y De s i g n Co u n c i l Wi n c h e s t e r Ho u s e, 2 5 9 - 2 6 9 Ol d Ma r y l e b o n e Ro a d, Lo n d o n N W 1 5 R A

FOOTBALL

ASSOCIATION

Contributors

Introduction-

I CONTENTS

1 .0 What are viewing standards for seated spectators? 7

1.1 How are sightlines calculated?

1.2 ‘C’ Values

1 .3 Angle of rake

1 .4 Riser heights

2 .0 How can existing terraces be adapted for seating? 10

2 .1 Every case is different

2 .2 How can terraces be reprofiled to provide good sightlines?

2 .3 Ground conditions

2 .4 How will the conversion affect capacity?

2 .5 Numbers v. comfort

2 .6 How will the conversion affect the layout of gangways?

2.7 How will the conversion affect the layout of turnstiles and exits?

2.8 Conversion costs

3 .0 What seat dimensions are required? --- 13

3 .1 The seatway, or clearway

3.2 Seating row depth

3 .3 Useful seat depth

3 .4 Seat width

4 .0 How many seats can be installed between aisles? 1 5

4 .1 Current guidelines

5 .0 W hat types of seating are available?--- 15

5.1 Bench seats

5.2 One-piece seats without backs

5 .3 One-piece seats with backs

5 .4 Tip-up seats

6 .0 What types of seat frame are available?--- 17

6 .1 Top tread or nose fixed seats

6.2 Tread or floor fixed seats

6 .3 Riser fixed seats

6 .4 Tread and riser fixed seats

7.0 What materials and finishes are advised?--- 18

7.1 Seat materials

7.2 Seat frame materials

7.3 Seat frame finishes

7.4 Durability of finishes in different locations

7.5 Fixings

8 .0 What colour seats should you choose?--- 20

8 .1 Stability

8 .2 Cost

8 .3 Colour mixing

9 .0 What flame retardancy standards are required?--- 20

9 .1 Current standards

9 .2 Design factors

1 0 .0 Are there any other factors to

consider?-1 0 .consider?-1 Seat strength

1 0.2 Drainage

1 0 .3 Ease of cleaning

1 0 .4 Vandal-proof fixings

1 0 .5 Ability to number seats

1 0 .6 After sales service and maintenance contracts

1 0.7 Press box seating

1 0 .8 Comfort and event usage

1 0 .9 Retractable and demountable seating

1 0 .1 0 Costs

1 0 .1 1 Football Trust grants

1 0 .1 2 Schemes for Football League clubs

21

For ease of reference, a checklist of the main points in this publication appears on page 23

For information on how the FSADC can help you contact professional advisors, seat manufacturers and suppliers, see page 24

For information on future FSADC publications see page 24

The FSADC would like to thank members o f its Architects’

Working Pa,rty for assistance in compiling this booklet:

Geraint John (FSADC and Sports Council), Terry Ward

(Husband Design Group) and Stuart Wallace (Miller

Partnership). Additional contributions were made by B ill

Gilson, Duncan MacLean and Ja y Parrish. The Courwil is

particularly indebted to the following for their specialised

contributions to the three main sections:

Sightlines: R o d S h ea rd Dip Arch ARIBA ARAIA is a

partner with the Lobb Partnersh ip. He was architect for

Watford’s Stanley Rous Stand, in 1986 and Twickenham ’s

South Stand in 1981. He has also designed a number o f major

qmndsta.vds, stadia,, racecourses and sports facilities in

B ritain and overseas (including Silverstone, New Delhi and

Kuala Lumpur). Other commissions ham taken Sheard to

_

sports and recreation centres in Jersey, Goa, UAE, Australia

and Taiwan. A regular speaker and writer on aspects o f

stadium design, he has also been involved with, the IAI(S

European Stadium working party, particularly on matters o f

crowd safety. Exam ples o f his award winning work ham been

exhibited a t the Royal Academy o f Arts, and Sheard is now a

member o f the FSADC’s Architects’ Working Party.

Conversion o f terracing: E rn e st A th erd e n Dip Arch RIBA is

Senior Partner w ithAlherden Fuller. Awarded the Rome

Scholarship in Architecture in 1960 he spent time in Italy

studying the noted stadia o f Pierluigi Nervi, before designing

his first grandstand a t Manchester Racecourse in 1961. In

1963 Atherden began the first phase o f Old Trafford’s redevel­

opment (in which he was largely responsible for incorporating

the first executive boxes a t a European football ground), and

remains closely involved with the stadium to this day. He has

also designed stands for Wolves (1980), Tottenham (1981) and

Liverpool (1991), and has overseen safety work at Liverpool

and Everton. In 1986Atherden was appointed by Wembley

Stadium to undertake refurbishment o f the stadium. He is also

a member o f the FSADC’s Architects’ Working Party.

Seat types: T ony S h e rra tt BSc represents the B ritish

Association o f Spectator Equipm ent Suppliers (BASES), a

trade association allied to the B ritish Sports and A llied

Industries Federation. Widely experienced in the manufacture

and design o f stadium seating, he is Managing Director of

Iiille Auditorium Seating Limited, based near Warrington,

and during the last 17 years has been involved at over 30

football grounds. A constant advocate o f quality seating,

Sherratt most recently oversaw the installa tion o f more than

40,000 seats a t Twickenham and Lords.

---

The Football Stadia Advisory Design Council was established

F O O T R AT J

J

SITADT A

in August 1990 on the recommendation o f Lord Justice Taylor

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XXLVIX

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pm d e d j ointiy by fjie Football League and the Football

A T W T Q n i T V

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Association. Its aim, in publishing booklets such as this and

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V l l O U J a I J J J u O l v X L N

by developing further research, is to encourage improvements

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in standards and a greater awareness o f stadium design. For

Welcome to the first in a series o f FSADC information booklets

on specialised aspects o f stadium design for football

As no-one in the the industry m il need reminding, seating is

one o f the principal issues facing football throughout Europe

du ring the 1990s, and while it is not for the FSADC to comment

upon the current debate surrounding the issue, the Council 'is

fu lly aware o f the difficulties many Football League clubs face

in implementing the Taylor Report1.

A League survey conducted in early 1991 found that some

852,000 seats w ill be required by the 92 clubs in order to con­

vert their grou nds to all-seaters. Countless more seats w ill no

doubt be needed in the non-League sector.

Yet even before the

Taylor

Report’s publication in

1990

the

ratio o f seats:standing places was already changing, largely

owing - it is true - to the reduction in terrace capacities, but also

to an increase in the number o f seats provided.

This is particularly true among First Division clubs. In Dec­

ember 1990 seats fo m e d an average o f 51.5% o f capacity in the

First Division, compared with 41.6% for the same clubs in 1982.

Comparative figures show a m e in the Second Division from

23% in 1982 to 34.5% in 1990, in the Third Division from 19%

to 29%, and in the Fourth Division from 14.3% to 23%.

The provision o f more seating raises a number o f other issues,

not least the need at many grounds to build new multi-tiered

stands to m aintain reasonable capacity levels and the require­

ment to cover seats placed on existing terraces. Both these issues

w ill be tackled in forthcoming FSADC information booklets.

Apart from the obvious problem o f funding the installation of

seats, there appear to be two further dilemmas.

Firstly, the FSADC recognises that for many clubs there is a

conflict between the need to provide as m any seats as possible -

so as not to lose capacity - and the need to provide comfortable

seating. Compromise is inevitable, but it should only ever be as

the result o f considered judgm ent by professional advisors.

Uncomfortable or poorly installed seating is less likely to

receive the approval o f supporters, and may even contribute to a

higher level o f damages and ill-behaviour, whereas experience

suggests that the most hardened sceptic can be won over by the

provision o f a comfortable, unhindered view o f the action.

Secondly, experience shorvs repeatedly that although adopting

cheap solutions for seating might seem attractive in the short­

term it w ill ultim ately prove to be a false economy. This applies

not only to the choice o f seat itself but also to the seat frame, its

fixin g s and the preparation o f the seat tread.

This first booklet therefore seeks to guide clubs, architects and

other interested parties through the basics o f three main aspects

o f the subject:

• viewing standards for seated spectators

• the conversion o f terradng to seating

• an examination o f available seat types

Each section has been written by experts in the field, taking

into amount the logistical problems facing clubs, but at the same

time recommending, wherever possible, that high standards be

achieved,

For easy reference a summary o f recommendations appears on

page 23, follo wed on page 24 by information on how the FSADC

can help with farther advice.

Both the FSADC, and B A SE S

-

which represents the seat

suppliers - hope that the information in this booklet w ill be o f

value to clubs in all sectors o f football, League and non-League,

and welcome any enquiries, comments or suggestions for this, or

any future publications.

INTRODUCTION

1. Inquiry by Lord Justice Taylor into the Hillsborough Stadium Disaster, Final Report, HMSO Cm 962, London, Januaiy 1990

1.0 WHAT ARE VIEWING STANDARDS FOR

SEATED SPECTATORS?

It goes without saying that every person attending a football match should be able to enjoy an unobstructed view of the event he or she has paid to see. Unfortunately in many cases that is an elusive goal, given the stadium infrastructures we have inherit­ ed from previous generations.

However, there can be no excuse for instal­ ling new seating which does not meet mini­ mum viewing standards. By this, we do not mean the removal of physical obstructions.

Viewing standards in this case refers to the ability of the seated spectator to see a predetermined focal point (on the pitch) over the top of the head of the spectators sitting immediately in front. This viewing standard is often referred to as the 'sightline'.

(Note: Sightlines should not be confused with ‘viewing distances’, the measurement of how far the spectator is from certain parts of the pitch. These will be examined in forthcoming FSADC information booklets.)

It is patently self-defeating to invest in high-quality seating if spectators cannot see the game fully and in comfort. And yet false calculations have often been made by inex­ perienced architects and builders, some­ times at great cost to the clients and considerable irritation to the supporters.

The FSADC therefore strongly advises that clubs employ experienced professionals for these important calculations, and that computer analysis is the best way to perform the task accurately2.

1.1 How are sightlines calculated?

There is a simple mathematical calculation to work out the sightlines for seated specta­ tors, but it becomes complicated once one realises that the calculation must be made for every row of seating and for every vari­ able which the design throws up, such as variations in the rake of the stand, the cur­ vature of a particular corner, or the height and depth of the concrete treads and risers.

The basis of the calculation is explained in Diagram 1 (see next page), which shows how the formula is derived from simple trigonometry. The essentials are as follows:

1.2 ‘C’ Values

An accepted international standard of the distance between the centre of the eye and the top of the head is 120mm. This mea­ surement is referred to as the ‘C’ value.

Research by NASA in the USA found that for 95 per cent of American adult males the distance between the centre of the eye and the top of the head is 127mm or less, and

in 5 per cent of adult males 104mm or less. In some sporting venues, for example

racecourses, where hats are often worn, the ‘C1 value is sometimes increased to 150mm or even 200mm to ensure good sightlines. But at a cricket ground, where the action seldom comes close to the stands, a ‘C’ value of 90mm to the outer area of the play­ ing field might be acceptable. This is because we have a tendency to tilt our heads backwards slightly as the action moves closer towards us, thus reducing the distance between the centre of the eye and the top of our head to only 90mm.

At a football match the action moves to all parts of the pitch, so ideally every football stadium would be designed to provide a ‘C’ value of 120mm to all parts of the pitch.

But, as Diagram 2 (see next page) illus­ trates, a higher ‘C’ value has consequences for the rake (or angle) of the stand and its

height, a particular problem for larger stadia, especially multi-tiered designs. As a result, in some areas of large stadia it is difficult to achieve a ‘C’ value greater than 60mm.

Diagram 3 (page 9) shows how bringing the touchline nearer to a stand, while main­ taining a 'C' value of 120mm, affects the height of the stand.

1.3 Angle of Rake

The angle of rake is the measurement of how steeply or gently the stand or terrace slopes down towards the touchline, and since this is an important element in creating good sightlines it is worth under­ standing. We will, however, be referring to the rake of stands in future FSADC publica­ tions concerned with stand design.

The ideal football ground would have as many spectators as close to the action as possible, but that would entail very steeply raked stands. Italian codes of practice sug­ gest that a stadium rake can be as steep as 41 degrees, and rakes of over 35 degrees are to be found in North American stadia.

In the UK, however, the angle of rake is determined by safety limits for staircases. Before its abolition the GLC set a limit of 35 degrees for stands within its jurisdiction.

The Green Guide currently recommends a rake of no more than 34 degrees, but this may be increased if additional compensatory measures are provided (see Green Guide3 para. 182 pp 38-9).

Rakes of more than 3 4 degrees can induce a vertigo effect, and it is noticeable that in the steeper Italian stadia, handrails are provided in front of each seat. Shallower rakes are usually found on lower tiers, with the upper decks of stands being steeper in order to accommodate more spectators closer to the pitch with an acceptable standard of view. 2. The FSADC is compiling a register of professionals with experience of or interest in stadium design. For details of how to use the register, please see page 24.

3. Green Guide - the Guide to Safety at Sports Grounds, HMSO 1990.

Diagram 1. Viewing standards for seated spectators - illustrations of terms

'C' Values • 150mm: Excellent viewing standards • 120mm: Veiy good • 90mm: Reasonable. This should be the minimum for newly constructed seated areas • 60mm: Below minimum standards, only acceptable in certain sections of very large stadia. Spectators will only be able to see between heads of people in front.

Point of Focus

D = Distance to point of focus R = Height to point of focus

\ z ___

V VALUE A \ RISER HEIGHT 4 / TREAD DEPTH or Seating Row Depth

To determine the riser height required for a desired 'C' value, use the calculation cited on page 9 opposite

Diagram 2. The effect of changing 'C' values

C = 150 C = 120 C = 90 C = 60 6 metres

POINT OF FOCUS - typically near touchline

The vertigo effect in such upper tiers can be lessened by reducing the number of rows in that tier, ie. the steeper the rake, the shorter the run of treads should be.

Diagram 4 (see below) shows how the height of a stand is affected by the change in height of the first row of seats, when at the same time trying to maintain a ‘C’ value of 120mm.

1.4 Riser heights

Viewing standards will be affected by the riser height of each seating row. In small, single-tiered stands the riser height will be constant.

In large and multi-tiered stand the riser heights should be varied, in order to provide optimum sightlines for each seat.

For ease of construction designers often divide the tier into facets (ie. several rows treated as one), adjusting the riser height slightly between facets. The difference between each facet’s riser height may vary by only a few mms, but the overall effect on viewing standards can be quite significant.

The following calculation is used to deter­ mine the riser height:

N

= (R

t

C)

X (D ±-I) _ r

D Where:

N = riser height

R = height between eye and point of focus C = viewing standard, ie. the ‘C’ value D = distance from eye to point of focus

(typically the near touchline)

T = tread depth, ie. depth of seating row Using a typical set of figures (see

Diagram 5), this is how the calculation looks in practice. Note that this calculation must be done for every row. (All measurements in mm): N = (6 .0 0 0 + 120) x (2 0 .0 0 0 + 8 0 0 ) _ « nnn 20,000 therefore: ^ _ (6 ,1 2 0 ) x (2 0 ,8 0 0 ) _ @ qoo 20,000 therefore: N = 6 ,3 6 4 .8 - 6 ,0 0 0 therefore: N = 364.8m m Diagram 5. Worked example of calculation for riser height

Note th at th e figures R, D & T for position A are use d to determ ine th e riser height N for position B

Diagram 3. The effect of bringing the point of focus nearer to a stand

9.2m I Jfk. 7.3m 'C = 1 2 0 9m 6m

Moving the point of focus 3m nearer the first row adds 1.9m to height at rear

POINT OF FOCUS

Diagram 4. The effect of raising the height

of the first row of seats

13m 11.1m 6m

9.2m 34 degree rake

Raising the first row provides better viewing standards, but also has the effect of adding to the height at rear

2.0 HOW CAN EXISTING TERRACES BE ADAPTED

FOR SEATING?

4. Details from the Football Trust, Walkden House, 10 Metton Street, London NW12EJ. Tel. 071 388 4504

10

It should be stressed that the conversion of standing to seated accommodation is not confined simply to putting seats onto exist­ ing terraces, be they timber or concrete. Many other factors have to be considered if the new seating is to conform with all the necessary criteria (such as correct sight­ lines, rakes, gangways etc.)

Clubs intending to embark upon a conver­ sion project of this nature should consult with the local licensing authority (that is the authority responsible for the issue of the Safety Certificate under the Safety of Sports Grounds Act 1 975 or the Fire Safety and Safety of Places of Sport Act 1987).

There should also be an input from the police and fire authority prior to any con­ struction work being undertaken.

It is also important to note that in order to qualify for grant aid, certain other criteria must be met.

• The Football Trust must be notified with an accurate estimate and description of works, followed by three competitive tenders and approval by the Trust before work starts4.

• The proposed scheme must fall into the Trust’s designated category for funding, although the conversion of terraces from standing to seating normally does.

Guidance from the Football Trust should be sought in any event.

2.1 Eveiy case is different

Convenient though it would be if hard and fast rules could be laid down for the conver­ sion of standing accommodation to seats, the truth is that conditions vary enormously from one venue to another.

The following sections seek to cover some of the most common situations.

2.2 How can terraces be reprofiled to

provide good sightlines?

There are four basic ways to reprofile an existing terrace to prepare it for seating.

Each one is primarily geared towards pro­ viding adequate viewing standards for seated spectators.

It must be stressed that high standards of finishing, especially when using concrete, are absolutely essential for trouble-free seat installation and subsequent maintenance o f the seats.

Note also that because of the reduction in capacity from standing to seating, the ‘live load’ on the terrace or on the stand’s struc­ tural members will also be reduced.

1. If sub-soil conditions allow - ie. the ground can bear the weight - the terraces can be reprofiled with mass concrete. (See Diagram 6 opposite page).

2. Pre-cast concrete units can be used to the same effect, but solid foundations will still be required, and there may be ‘lead-in times’ to consider (ie. the units will need to be ordered in advance).

3. Should the existing terrace not be considered suitable to carry the imposed dead load of mass or pre-cast concrete, or where the terrace is very narrow (such as the enclosure area in front of an old stand), or where the stand is unlikely to be retained for much longer, it may be simpler and cheaper to reprofile using other methods.

These may include the following:

a. lightweight concrete: there are various methods of producing lightweight concrete, for example, creating air voids in the con­ crete, omitting fine aggregate or adding a foaming agent to the mix. The most readily used method is to use lightweight aggre­ gate, such as blast furnace slag or fly ash.

b. polystyrene blocks: used more com­ monly for building up roadway embank­ ments, this method involves creating a brick or blockwork grid, filling the voids with specially cut polystyrene blocks (thereby reducing the dead load) then laying concrete on top. It is more expensive than using mass concrete, being more labour intensive.

c. steel plates or GRP (Glass Reinforced Plastic) terrace units: these can be formed to provide the required terrace profile and supported on either a temporary or perma­ nent steel substructure fixed upon the exist­ ing standing terrace.

4. If the concrete is in prime condition and the treads and risers allow the new seats to be bolted directly onto the existing concrete, the required sightlines can be achieved by adjusting the height of the seating’s metal underframe.

This is by far the cheapest method of con­ verting terraces and providing good sight­ lines, but it should only be treated as a last resort or as a way of simply fine-tuning the conversion work.

Adjustment should only take place within the comfortable seating height range. BASES advises that the British Standard for seat heights is 445m m s, but it would be acceptable to vary this within the range 4 4 0 - 460m m s to enable sightlines to be improved.

Diagram 6. Reprofiling terraces using mass concrete

Existing barrier removed

Riser fixed tip-up seats New barrier

Existing barrier

removed • - *. ' Exi sti ng

' ; -a%jji seated New seated terrace. 'r - ^ terrace

1--- _{Existing standing} terrace

1--- I---New drainage channel

2.3 Ground conditions

A considerable number of standing terraces are built on ‘filled’ ground, the result of a ’cut and fill’ process undertaken when the stadium was first laid out. Other terraces have been formed by the dumping of ash, building rubble, or tube excavations at some London venues. Some clubs with such bank­ ing have found that the sub-soil conditions are inadequate for remodelling or for adding roofs.

The surfaces of these terraces also causes concern. Invariably they are covered in weak concrete, asphalt, paving slabs or a combination of materials.

In severe cases, prolonged neglect has meant these terraces are beyond economic repair and certainly totally unsuitable for fixing seats upon.

The FSADC strongly urges clubs with ‘filled’ banks o f terracing to carry out a thor­ ough ground investigation in conjunction with a Consulting Structural Engineer to determine the nature o f the sub-soil and establish the load bearing capacity.

Where ‘land fill’ sites have been used, a geo-technical expert should also be consulted

to advise on ground contamination prob­ lems such as methane gas or toxicity levels (which could have a detrimental effect on subsequent concrete constructions).

2.4 How will the conversion affect

capacity?

Calculations will vary from stadium to stadium, but from a survey of twelve recent conversions it has been found that new seats can be provided in lieu of standing at the ratio of approximately 1:2 (ie. a terrace

holding 5 ,0 0 0 standing spectators will accommddate 2 ,5 0 0 seats).

2.5 Numbers v. comfort

The two would seem to be mutually exclusive. Clubs obviously desire maximum comfort levels. Ultimately a responsible compromise will have to be reached to satisfy safety requirements, but it should not be forgotten that comfortable seating is more likely to be favourably received (arid possibly even treated) by sceptics, and that uncomfortable spectators may not give the new seats a second chance.

2.6 How will the conversion affect the

layout of gangways?

Although the numbers will be reduced for that section of the stadium (see Section 2.4), it is unlikely that there will be suffi­ cient access points or vomitories to serve individual gangways.

Diagram 7. Reprofiling terraces

using concrete infill on treads

For riser fixing the concrete riser height must be at least C oncrete infill to alternate

s te p s to form new seating 200mm. See

Note that the provision of more access points, such as vomitories, is preferable to the use of lateral gangways, which take up considerably more space, thus adding to the reduction in capacity.

Nevertheless, a system of lateral gang­ ways may be necessary to achieve an even distribution of spectators.

Each of these lateral gangways may in turn serve a number of radial gangways, and they will need to be of sufficient width to accommodate the cumulative capacity of all spectators using this circulation route.

Where possible, avoid a situation where seats are provided on one side of a gang­ way only, as this is not an efficient use of circulation space.

Diagram 8 (below) shows two relatively modern terraces which have been converted and illustrate how radial gangways are fed either from the front or rear.

Note however that although front lateral gangways can sometimes assist in satisfy­ ing the Green Guide para 3 0 8 (which recom­ mends walkways between the pitch and ter­ race), the movement of people along this gangway during a match can lead to ill feel­ ing from spectators in the front rows.

There will be more detailed information concerning circulation within stadia in future FSADC booklets.

2.7 How will the conversion affect the

layout of turnstiles and exits?

The numbers of turnstiles and exit widths should not be a cause for concern because

there is likely to be an overprovision due to the reduction in spectator capacity.

However, the location of these facilities can be critical in establishing a satisfactory circulation pattern for spectators, especially on large areas of terracing, where entrances and exits are sometimes grouped in

strategic positions.

It may be necessary in certain circum­ stances to consider relocating turnstiles and exits to achieve a more even distribu­ tion relative to the proposed seating layout, in order to avoid unacceptably long travel distances and reduce potential bottlenecks and funnelling.

2.8 Conversion costs

Because ground conditions vary so much it is impossible to provide an accurate guide to conversion costs.

A Football League survey showed that among twelve clubs to have installed seat­ ing on former terraced areas during 1990, the costs (including ground preparation, new barriers, seat purchase etc) ranged from approximately £ 1 8 per seat, where basic seats were installed on existing terracing, up to £ 1 0 1 where a whole new turnstile and entry system had also to be provided for greater safety.

The majority of costs fell within the £3 5 - 75 cost bracket.

Note that the Football Trust provides grant aid at 75 per cent o f approved expenditure, up to a ceiling o f £ 7 0 per seat installation costs (see Section 1 0.1 1).

12

Diagram 8. Examples of lateral gangway layouts on newly converted terraces

Vomitory

Gangway-Lateral walkway at front

Vomitory Lateral walkway at rear

Diagram 9. Illustration of terms and measurements for tip-up seats

i i

*

^

- F

A Seat down dimension D Useful seat depth B Seatway or Clearway E Seat back overhang C Tipped dimension F Seating row depth

or Tread depth Seat width measured 4 /-'b e tw e e n seat centres Riser height Seatway or Clearway Seating row depth or Tread depth

3.0 WHAT SEAT DIMENSIONS ARE REQUIRED?

The Green Guide covers the subject of seat­

ing dimensions on pages 39-40. While appreciating that clubs wish to install as many seats as is safely practical, the FSADC advises that certain minimum dimensions are too small for comfort, and fall some way below other international standards. See Diagram 9 above for an explanation of terms.

3.1 The seatway, or clearway

As can be seen from Diagrams 9 and 10, the measurement between the foremost projection of the seat (if a tip-up seat, in the tipped up position) and the back of the seat in front is called the 'seatway'. The Green Guide uses the term 'clearway'. This mea­ surement is important for two reasons.

The seatway is the passage along which spectators and other personnel must squeeze past other spectators. Obviously, the narrower the seatway the more difficult it is to pass by.

A narrow seatway also creates problems for the occupier of the seat, not only when standing up to allow others to pass, but also when sitting.

The Green Guide recommends a minimum clearway o f 305m m . For non tip-up seats, however, the FSADC recommends a pre­ ferred minimum o f 400m m

If installing seats with armrests, the pro­ jection of the armrests should not lessen the the 305mm minimum seatway measurement.

Note that in Scotland, different criteria apply. The Scottish Building Regulations (E2.63) state that in rows o f up to 1 1 seats with one gangway or 2 2 seats with two gangways, the minimum seatway must be 400m m . In longer rows the minimum increases to 500m m . (See also Section 4.)

3.2 Seating row depth

As can be seen from Diagram 9, the depth of the 'seating row’ is the depth of the terrace tread on which the seat is placed.

The Green Guide advises a minimum seating row depth of 610mm (which includes the minimum 305mm seatway).

However, the Green Guide goes on to recommend that for comfort the seating row depth should be 760mm.

BASES5 recommends the following mini­ mum seating row depths and seatway dimensions. (Note that the seating row depth always includes the measurement for the seatway.)

Row depth inc. Seatway

Bench or tractor type 700mm 400mm

Fixed seat with back 900mm 400mm

Tip-up seat with back 760mm 305mm

BASES recommends that for new construction, wherever the option exists, clubs aim for a row depth measuring at least 760mm, and 8 00m m if at all possible.

Diagram 10. Dimensions for bench seats

Minimum seating row depth recommended 700mm. Minimum seatway recommended 400mm 5. BASES {British Association of Spectator Equipment Suppliers), 23 Brighton Road,' South Croydon, CR2 6EA. Tel. 0 8 1 6811 242.

13

3.3 Useful seat depth

Diagram 11. Sections showing how measurements can

vary between different types of tip-up seats

Example 1. Tip-up seat with a tipped dimension of 320m m , a seat-down dimension of 500mm and a back overhang of 100mm:

3 2 0 100 K-^ — 5 0 0 — K-^ K-^ S e a t w a y ) K-^ I N ^ d e p t f f 3' / ^

¥

¥

e r r '. / _ S e a t i n g ro u t- \ depth

Seating Row Depth Seatway Useful Seat Depth

625 305 525

660 340 560

760* 440 660

* FSADC recommended standard

Example 2. Tip-up seat with a tipped dimension of 210mm, a seat-down dimension of 470m m and a back overhang of 70mm:

4 7 0 Seat way ^ 210

I

Useful seat 'depth 7 0

4

c:

i

c : Seating row depth

Seating Row Depth Seatway Useful Seat Depth

625 415 555

660 450 590

760* 550 690

* FSADC recommended standard

(The equivalent recommendations for seating row depths in Germany and the USA are 800mm and 762mm respectively. In Australia the State of Victoria stipulates a seating row depth of 850mm.

There is another reason for recommend­ ing a seating row depth of 760 - 800mm.

Where riser heights go above 380mm, which will occur in stadia holding more than approximately 2 0 ,0 0 0 spectators, a tread depth of 760mm or more allows two steps of 190mm risers to be placed in the aisle (see Diagram 12 right).

There is a third, crucial dimension which affects the comfort of seated spectators. BASES call this dimension the 'useful seat depth’. This is the horizontal distance between the back of the seat, measured at seat height, and the rear of the back of the seat in front (see Diagrams 10 and 11).

The New Metric Handbook (ed. P.Tutt and D.Adler, Butterworth 1990) found that 90 per cent of males in the 18-40 age group measure between 568 - 660mm from the rear of the buttocks to the front of the knee. The average measurement is cited as 614mm.

In order to cater comfortably for the majority of spectators therefore - and note that average sizes are gradually increasing - conditions should ideally allow for the provi­ sion of a 'useful seat depth' of at least 660mms.

Another factor affecting the 'useful seat depth' is the height of the riser, since the position of the knees can be affected by the height of the back of the seat in front. Riser heights of up to 200mm or over 400mm do not usually cause problems, as the knees either fit inside the back of the seat in front, or remain above it.

Before purchasing, check all dimensions with the seat manufacturers because, as Diagram 11 illustrates, the varying dimen­ sions of different seat models will affect the 'useful seat depth’ created on different seating row depths.

3.4 Seat width

Seat widths are often expressed in terms of the distance between two seat centres (see Diagram 9). The minimum width, according to the Green Guide, should be 460mm if the seat has no arms. BASES adds that where seat-for-seat replacement is being consid­ ered, a width of 450mm is acceptable.

The Green Guide minimum for seats with arms is 500mm. BASES consider that 490mm is acceptable.

Note that when calculating the length of a row of seats, allowance must be made for the end of row supporting posts.

For example, ten seats at 460mm centres require 4600mm plus approximately 75mm (depending on type of seat chosen).

Diagram 12. Riser heights and aisle

steps

Aisle steps \ Terrace riser

...

Seating row 1 ^ depth ^

4.0 HOW MANY SEATS CAN BE INSTALLED

BETWEEN AISLES?

4.1 Current guidelines

The Green Guide states in para 187: “the number of seats in a row should not normal­ ly exceed

a. 14 where there is a gangway at one end only

b. 2 8 where there is a gangway at both ends

The FSADC endorses these figures.

BASES suggest in addition that BS 5588 Part 6 199 1 6 should be the guide where escape route distances are taken into con­ sideration.

Note that in Scotland the number o f seats between aisles has a direct bearing on the minimum seatway measurement (see Section 3.1).

(It is interesting to note that this figure of 28 seats per row compares with 22 in the USA and Australia, 48 in Italy and 9 6 in Germany. In English theatres the maximum is 22 seats per row.)

5.0 WHAT TYPES OF SEATING ARE AVAILABLE?

Ideally clubs should opt for the highest

quality of seat type they can afford.

Practically, however, it may be necessary to install different seat types in different parts of the stadium.

5.1 Bench seats

Continuous bench seating without a back support was sometimes used to provide cheap seating in British football grounds before the 1980s and is common at older stadia in Europe. It usually consists of solid concrete forms or wooden planks placed on concrete plinths.

Nowadays, in order to qualify for current grants from the Football Trust, bench seat­ ing must have individual indents to identify each seating position.

Modern versions, sometimes called multi­ ple seats, are available in aluminium or moulded GRP (Glass Reinforced Plastic), with, if necessary, a metal underframe which can be fixed directly onto the terrace. This type of seating is cheap, easy to clean the actual seat (though harder to clean around the underframe) and some would argue that it is safer because it allows spec­ tators to step over the seats in the event of an emergency.

However, it is also easier for spectators to stand on bench seats (which in itself is a danger) and therefore the seat material and metal frame must be more robust.

Seating of this type should only be consid­ ered for the cheapest areas of admission.

5.2 One-piece seats without backs

Individual seats without backs - sometimes called ‘tractor’ seats - are available for fix­ ing directly onto the terrace tread.

Sometimes an additional metalwork understructure is necessary to achieve the correct seat height.

5.3 One-piece seats with backs

As with tractor seats, these can be fixed directly onto the terrace tread or placed upon a metal understructure.

They have no moving parts and are there­ fore easier to maintain than tip-up seats with a back.

However one-piece seats with backs take up considerably more room than either backless or tip-up seats, requiring a 'seat­ ing row depth' of 900mm compared with the recommended 760mm for tip-up seats (see Section 3.2, page 14).

In common with tractor seats, these types are more likely to be stood upon by specta­ tors, so they must be strong, but they are also easy to clean and are cheaper per unit.

5.4 Tip-up seats

This is the most common form of seating in places of public entertainment and, as a survey of Football League clubs showed in 1991 (see Introduction), it is also the pre­ ferred type of seating at major football stadia.

This is because tip-up seats take up less space, are easier to clean around, and allow spectators, the police and first-aid person­ nel to pass more freely along rows, a vital consideration during an emergency. Tip-up seats are also less likely to be stood upon during a game.

A further advantage is that individual seats can be upgraded by the addition of fixed cushioning, thus allowing you to pro­ vide greater comfort without major outlay. Note that some manufacturers of tip-up seats use the same mouldings for both the seat and the seat back, which can lead to lower costs and simpler replacement and maintenance procedures (although some people may judge there to be a slight loss of comfort).

6. BS 5588 Part 6 1991: 'Fire precau­ tions in the design, construction and use of buildings'. HMSO 1991.

Tip-up seats can be supplied either with indi­ vidual fixings or linked together using com­ mon supporting posts, fixed either to the ter­ race tread or to the terrace riser (see Sections 6 .2 - 6.4).

There is a choice of three types of tip-up arrangement:

1. the spectator must manually raise the seat after use 2. the seat is counterweighted to

raise automatically

3. the seat is spring-loaded to raise automatically

The second type is likely to be more prac­ tical for general stadium usage. The first type is not recommended because some safety officers may determine that the mini­ mum 'seatway' of 305mm (see Section 3.1) be measured when the seat is in the down position, whereas for types 2 and 3 the measurement is made with the seat in the up position (see Green Guide p.39).

When choosing a tip-up seat, examine the pivot arrangement for noise, ease of use, and the materials used.

A plastic stop (to prevent the seat drop­ ping down) and a nylon pivot bush elimi­ nates metal-to-metal contact and thus reduces the chance of corrosion.

Diagram 13. Different seat types, frames

and methods of fixing

Front tread or

nose fixed-

seats

Tread fixed

seats f T seats

--

J

Riser fixed

seats-Tread and riser fixed seats

T

J

C ~ _ "

c:

c:~

y

6.0 WHAT TYPES OF SEAT FRAMES ARE AVAILABLE?

The choice of seat must be made in con­

junction with the choice of seat frame (ie. its supporting structure).

Time, money and effort could well be saved by choosing a type of frame which, when being installed, requires the least amount of modification work to an existing stand or terrace.

Obviously space and money will be saved by installing rows of seats on linked frames rather than using individual frames for each seat, but if the terrace on which the seating is being installed is curved or angled some individual frames or short-run linked frames will be necessary.

Diagram 13 on the opposite page shows how different seat types can be supported and fixed in the following ways:

6.1 Front tread fixing

Front tread fixing is when the seat pan is attached directly to the leading edge of the terrace's concrete tread.

Seats can also be shaped to hug the nos­ ing of the terrace.

A concrete step of up to 400mm high is required to provide a comfortable sitting position, but lower heights can be supple­ mented by the addition of a shallow support­ ing understructure.

This type of fixing is most commonly found in the sunnier climes of Southern Europe and Latin America, where the stadium ter­ races were already designed for spectators to sit directly upon the concrete.

Note that front tread or nose fixed seats require a ‘seatway’ of 400mm compared with 305mm for tip-up seats. (Section 3.1).

6.2. Tread or floor fixing

Tread or floor fixing is when the seat’s frame is attached directly onto the terrace floor.

This method has the disadvantage of mak­ ing it harder to sweep litter from under the seat. A longer supporting seat post is also required, and this must be sufficiently strong to withstand the pressure of specta­ tors pushing the seat from behind.

It has also been found with tread or floor fixed seats that the actual fixings are sus­ ceptible to corrosion where poor drainage allows water to collect on the terrace floor.

This is a particular failing where older, or poorly maintained terracing is not upgraded before seats are installed, or where new concrete has been laid unsatisfactorily.

6.3 Riser fixing

This is the preferred method for fixing tip-up seats. In this case the seat frame is bolted to the riser of the terrace, leaving the floor clear for spectators to step back into and for litter clearance. However, you can only use this method of fixing if the terrace riser is sufficiently high - ie. a minimum of 160mm for wood risers and 200mm for concrete.

6.4 Combined tread and riser fixing

Where terrace risers are not quite high enough for riser fixings alone, for example between 150-200mm in concrete, there is a compromise version available whereby the seat fixings are attached to both the riser and the tread.

7.0 WHAT MATERIALS AND FINISHES ARE ADVISED?

For the seat, its supporting frame and its

fixings, a careful choice of materials is strongly advised. You should take into account how much wear and tear seats in certain parts of the stadium are likely to suffer, how exposed the seats will be to the elements, and whether it is cost-effective in the long-term to opt for the cheaper types.

Less robust seating may cost less but subsequent unit replacement and ongoing maintenance problems may soon wipe out the intitial saving.

The material of the seat frame and its finish are more important than the material of the seat itself. Choosing high quality fin­ ishing can extend the life of the metalwork by up to five times, and it is far cheaper to replace the seat than the metalwork. High quality, well maintained frames may last for 2 0 years or more, whereas it is almost certain that the seats and backs will need to be replaced within that period.

The durability of the seat itself depends on the material chosen.

7.1 Seat materials

The principle materials available for modern seating are Polypropylene (the most com­ mon), Polyethylene, Polyamide (Nylon), PVC and GRP (Glass Reinforced Plastic).

However, many football and sports grounds still use wooden seating extensive­ ly, and in a few cases metal seating.

Table 1 opposite offers a brief summary of the advantages and disadvantage of each material.

7.2 Seat frame materials

These are invariably metallic, usually fabri­ cated steelwork, although cast aluminium is available at a premium price. Technological advances have resulted in the development of moulded plastic seat frames, and it is possible that in time these will become widely used. At present however the FSADC is unable to comment on the durability or performance of this material.

7.3 Seat frame finishes

Apart from the material, the most important factor is the finish, because this can seri­ ously affect the long-term durability of the seat structure.

A number of finishes for metallic frames are available, with 'life expectancy to first

maintenance' varying from 1- 20 years, dependent on location.

There are three recommended finishes: 1. Electrostatically coated nylon powder 2. Hot dip galvanising to BS 729

3. Electrostatically coated nylon powder on grit blasted, hot-dipped galvanising Finishes 2 and 3 should be specified where weathering is likely to occur. Finish 1 could be used at the rear of stands, where the seats will be more sheltered from the elements.

Finish 3 is the most expensive and should be carried out to BS 729, using high quality steel. The nylon coating adds resistance to U.V. rays, acid rain, salt and heavy impact. (An equivalent to nylon coating is acceptable providing it is shown to be both technically sound, using the accelerated weathering test to BS 546 6 Part 1, and it forms a bond to the metalwork which will not peel off if its surface is broken.)

In both cases, check to find out if a means of economically maintaining the metalwork is available,

Note that cheaper finishes are more sus­ ceptible to cracking, chipping, rust formation and peeling, and are much harder to repair.

7.4 Durability of finishes in different

locations

The geographical location of your stadium will affect the durability of the seat frame. The weather in inland locations, for example, will be less damaging to the metalwork than in humid, damp, polluted or coastal regions.

Minimum guarantees to first maintenance of five years on plastic/nylon-coated metal­ work, eight years on galvanised metalwork and ten years on nylon-coated galvanising should be expected.

7.5 Fixings

The seat frame should be bolted to the con­ crete with rustproof fixings. Stainless steel bolts and fastenings are preferable. They add little to the cost but considerably enhance the seat’s long-term appearance and ease of maintenance.

Note also the advice in Section 6.2 re: corrosion of fixings.

TABLE 1. SEAT MATERIALS

In the UK, the most commonly used material for stadium seating is Polypropylene with UV (ultra-violet stabilizers) and absorbers (see first column). A number of other materials available on the market are compared in the table below, compiled by BASES. Wood and metal are still used, but have been excluded as they are both uneconomic when compared to plastics. It should be noted that the figures given for the 'raw material cost factor' are for information only, and do not necessarily reflect unit costs to the buyer.

U.V

Polypropylene

U .V ./Fire Retardancy Polypropylene

Raw material cost factor Availability Colour Range Volume Manufacture Flame Retardancy to BS 5 8 5 2 Reaction to low temperatures (-5° C) Reaction to high tem peratures(+50° C) Reclamation and Recycling W eatherabllity Deformation Number o f years in production 1.0 1.4

Readily available Limited Very Good Good Very Good Good

Ignition Source 0 Ignition Source 7

Brittle Very Good Easy Good Recovers 27 Brittle Very Good Moderate Good Recovers 0 4

U.V. High Density Polyethylene

1.2

Readily available Very Good Very Good Ignition Source 0 Very Good Good Easy Good Poor

20+

Polyamide (Nylon) 3.2 Limited Limited Good Self-extinguishes Very Good Very Good Moderate Very Good N/A 19 P.V.C Compound

1.8

Limited Limited Good Self-extinguishes Very Good Very Good Specialised Very Good N/A

01

G.R.P. approx. 7.0 Limited Very Good Very Poor Self-extinguishes Very Good Very Good None Very Good N/A 25+

8.0 WHAT COLOUR SEATS SHOULD YOU CHOOSE?

7. For further details refer to BS 1006: B01C 'Blue Wool Standards'.

20

This is obviously a matter of choice, but it maybe worth considering a few technical quali­ ties and different approaches.

8.1 Stability

Every manufacturer has its own range of colours, but some colours are more suscepti­ ble to fading when exposed to ultra-violet rays (bright sunlight) and other extremes of weath­ er, such as acid rain.

Two factors which affect colour stability are the colour pigment itself and the level of addi­ tives in the mouldings.

To ensure that the best colour pigments are chosen for the location in question, light fast­ ness (ie. resistance to fading) is measured on what is called a Blue Wool Scale7. A perfor­ mance of 7 or 8 on this scale should indicate that a colour pigment will not fade too rapidly.

To ensure that the colour will last even longer - although no guarantees can be given because conditions vary, even within the same stadium - additives are necessary, namely UV stabilizer and absorber.

Full strength colours (eg. red, blue, black and green) are more stable than pastel varia­ tions (such as pink and sky blue). Vet sky blue has excellent anti-glare characteristics under floodlight.

Clubs who include black in their team colours may be interested to note that of all the colours, black is the best for colour stabili­ ty and for weatherability. Yellow and orange are not good for stability.

8.2 Cost

Costs vary according to colour. Choosing a

non-standard colour may lead to delays in delivery and a premium being charged. Similarly, you may have to pay more if you order smaller quantities.

Members of the Football League should refer to Section 10.12 to find out more about the League’s plans for bulk purchase.

8.3 Colour mixing

Apart from the now common use of multi­ coloured seats to spell out a club’s name, dif­ ferent seat colours can be used to differenti­ ate between blocks in the same stand. This may be considered a useful aid for ticketing and signage. A disadvantage of this system is that if the stadium is only half full the different colours detract from the overall impression of the stadium.

In several large stadia in Europe and the USA the same seat colour has been provided throughout, to create a unified, and often dig­ nified image overall. Very often this single colour is a neutral one - such as grey - so that the spectators provide the colour, rather than the seats. Very light colours, however, can be hard on the eye if there is only a small crowd. In Sweden, where attendances can be low, one stadium has used random colour seats (mainly blue, orange, red and yellow), which uncannily gives the speckled appearance of a full stand, even when few people are in attendance!

Note also the comments of one manager who complained that during reserve games, from his position in the dug-out he was unable to distinguish his own players against the backdrop of the empty seats, since the seats and players’ shirts matched exactly.

9.0 WHAT FLAME RETARDANCY STANDARDS

ARE REQUIRED?

Unfortunately Fire Officers interpret flame retardancy to different standards throughout the country, so clubs should be sure to establish what standards apply before pur­ chasing seats. Note also that not only the material of the seat but also its design affects the standard of flame retardance.

9.1 Current standards

A minimum Ignition Source 0 of BS 5852 Part 1 should be acceptable, especially where the seats are attached to concrete.

Upholstered seating should comply with Ignition Source 5 of BS 585 2 Part 2 , as stated in the Green Guide, para 184.

There are plastic products available which meet the higher flame retardancy standards of Ignition Source 5 of BS 5 8 5 2 Part 2 and which also have colour stability against UV rays and weather. At present, however, the

choice of colours is limited in these materi­ als and there is a price premium to pay.

Note also that some fire officers believe that the use of flame retardant additives means that when the seat does finally ignite it can produce dangerous toxic fumes, including bromides and carbon monoxide. Check with your Fire Officer first.

9.2 Design factors

Some manufacturers feel that when it comes to testing for flame retardance the design of the seat itself is at least as criti­ cal as the material used. Double skin forms (ie. blow moulded) with rounded or smooth edges are, according to this view, preferable to those with plain edges. Again however, there is a price to pay. Blow moulded seats are 50-100% more expensive than conven­ tional injection moulded seats.