Seating · SERVICE · REV 2026-10-06
Theatre seats
A tip-up seat is two decisions: shoulder and knee comfort while the spectator sits, and the clear width when the seat rises so people can pass. The adopted code names which width counts for egress. The fire report names fabric, foam, and shell together. Change the fabric and the report changes.
Definition
Centres are the dimension between seat axes. Row pitch is back to back. Comfort wants larger centres and pitch. Egress wants a clear gap, often between tipped seats, and the code limits it, not the catalogue. This page sets no legal millimetre. Sightline literature discusses a C-value around 90–120 mm, then project geometry and code fix it. It is not imposed from here.
Numbering matches the ticketing plan: one house-left direction, row letters, and the accessible seat’s number inside the same series. An accessible seat comes with a companion, distributed so it sees the show, not in a pocket with no sightline. Count and ratio come from the local code, not from this page.
When is this service needed?
Freezing capacity
The count is the result of centre, row, and aisle. Dividing area by a fictional seat is wrong.
Comfort against the aisle
Pulling centres closer raises the count and narrows the shoulder, and it may break exit width. The code decides the second.
A new fabric request
Before upholstery, not after. The report is for the build-up. Substitution restarts the test.
Distributing access
When the rows are drawn, not at the end of the project. A seat added in the aisle eats the width that was calculated.
Where it is used
Theatre houses
Long rows and side aisles or a centre aisle. Row length itself may be limited by the code.
Balconies
The sightline is harder and the movement tighter. The same seat may not fit if the riser height changes.
Speech halls close to theatre
If it stays a tip-up with no writing tablet. A tablet belongs on the auditorium-seat page.
Not an open stand
Fabric, foam, and a tip mechanism are not the assumption for sun and rain. That is a stadium seat.
Parts of the solution
The tip-up mechanism
It returns quietly and does not stay down under a passing foot. Clear width is measured with it tipped.
Centres and arms
A shared or own arm changes the real shoulder width. The catalogue may name a width that is not the clear width.
Fabric, foam, and shell
One build-up in the fire report. Replace any item and the transfer falls.
Numbering
A row plate and a seat number that match the ticket, including the accessible seat.
Accessible seat and companion
A place that sees, a movement space, and an adjacent companion as the code requires, not as the drawing finds easy.
Engineering considerations
Egress versus comfort
Two numbers. Widening comfort may cut the count. Narrowing it may break the code. Egress is not sacrificed for a capacity picture.
Row length
The number of seats between aisles may be limited by the code. A seat added at the end restarts the calculation.
Sightline
Eye height, the row in front, and C-value. A comfortable seat on the wrong riser does not see.
Fire only from the report
No class on this page. The certificate is for the named build-up from its laboratory.
Acoustics
An occupied seat absorbs. Occupancy is part of the RT60 criterion, not a fabric detail.
Materials
The tested fabric
The name in the report, not “something like it”. A colour may or may not be allowed inside the tested family.
Foam and shell
Part of the test. A foam swapped for comfort reopens fire.
Metal and the mechanism
Tip cycles come from the product sheet. This page gives no cycle life.
Related systems
Aisles and exits
A continuous clear width to the exit. The last seat does not creep into the aisle width.
Sightline and the platform
C-value with riser height. The detail is on the sightline page, not in the catalogue.
Light and numbering
A number unreadable in the step shadow misdirects the audience. Minimum light is from the code, not from here.
Acoustics and occupancy
Empty is not full for RT60. Handover names the condition.
Design sequence
- 01
Read the code limit for exit width and row length before drawing the centre.
- 02
Separate comfort width from clear width with the seat tipped. Do not use one in place of the other.
- 03
Draw the sightline with the riser. A seat that cannot see is not useful capacity.
- 04
Distribute accessible seats and companions inside rows that see.
- 05
Name the build-up in the fire report before the colour is approved.
Delivery sequence
- 01
Seats are fixed on the drawn axes. A drifted centre narrows the aisle at the end.
- 02
Clear distance is measured with seats tipped after installation, not only on the drawing.
- 03
The fabric that matches the report is fitted. A site substitute is rejected without a new sheet.
- 04
Numbering is installed to the ticketing plan and checked from the door.
- 05
The accessible seat is left free of a fixing that blocks transfer or the clear space.
Testing
Clear width
Measured on site as the code defines it. The catalogue figure is not the measurement.
The tip action
It returns fully and does not stay in the aisle. A sample of the row, not only the show seat.
Match to the report
Fabric, foam, and shell as written. No fire test is reinvented here.
Commissioning
A numbering plan handed over
It matches tickets and signs. A house-left conflict is closed before opening.
Accessible seats ready
Position, companion, and the route from the entrance. No chair is pulled on show night to open a space.
No class from this page
A copy of the report with the build-up is in the handover file. This page carries no certificate.
Maintenance
A tired mechanism
A seat that does not tip eats aisle width every night. Repair it before the aisle is counted wrong.
Reupholstery
New fabric reopens the fire question. The report, or its equivalent, comes before fitting.
Damaged numbering
A missing number misdirects the seat. Replacement is from the same system, not handwriting.
Common mistakes
Counting seats from area
The aisle, the platform, and access disappear in the division. The resulting capacity is unlawful or uncomfortable.
Open-pan width treated as the aisle
Egress is measured as the code defines it, often with the seat tipped.
Fabric with no report
Colour is not a class. Fire belongs only to the tested build-up.
All access at the back
A row that does not see, or a long route, because the drawing is easier. The code and the view reject that.
Short comparison
The comparison is a way to choose a path. It is not a product recommendation and it is not a code.
| Path | Fits when | Weakens when |
|---|---|---|
| A theatre tip-up | A show needs an aisle when people pass and comfort when they sit, indoors. | When the need is a writing tablet, a cinema recliner, or an open stadium. |
| A fixed seat with no tip | The row is short and the clear width is enough even while occupied, and the code accepts that. | When people cross a long row and the seat does not rise. The aisle disappears. |
| A cinema recliner | A long show with no writing, depth and pitch are available, and the lost capacity is acceptable. | In a spoken theatre that needs count and aisle. The recliner eats the row. |
Discussion ranges
Any number here is a preliminary discussion range from practice or a named reference. Replace it with the project criterion, laboratory data, and on-site measurement.
| Item | What is discussed | Limit of this page |
|---|---|---|
| Seat centres | The dimension between axes. A shoulder-comfort discussion, then checked against exit width. | No millimetre on this page as a legal limit or a product. Code, catalogue, and drawing together. The catalogue alone is not enough. |
| Back to back | Row pitch for the knee and for passing in front of a seated person. | Not automatically the exit width. Clear width with the seat tipped may be the item the code measures. No figure here. |
| C-value | Sightline clearance over the head in front. Literature often discusses about 90–120 mm. | Not imposed by this page. Riser geometry and the local code fix the value. A seat that misses it is not counted as if it sees. |
| Fire class | The result of the test report for the build-up: fabric, foam, shell. | No class and no certificate on this page. Change one item and the transfer into a quotation stops. |
What this page does not claim
No fire classification, absorption coefficient, sound pressure level, or legal capacity on this page may be copied into a quotation. Those values come from a product test report, a measurement, or the local code adopted for the project.
Questions designers and owners ask
Is the catalogue seat width the aisle width?
No. The aisle is a clear gap the code defines, often between tipped seats. Open-pan width is comfort.
Can I change the fabric later?
Visually, yes. For fire, no, unless there is a report for the new build-up. This page does not give the class.
How many accessible seats do I place?
Count and distribution come from the local code and the access strategy. There is no ratio on this page.
What is the correct C-value?
Literature opens the discussion around 90–120 mm. The project and the code fix the figure. This page does not impose it.
Does an occupied seat change the sound?
Yes. An audience is absorption. The RT60 criterion names the hall empty or full. ISO 3382-1 is the measurement in a performance space.
Technical sources
- The adopted local code
Exit width, row length, and accessible seats. This page does not replace it and does not carry a numeric limit.
- The seat test report
Fire for the named build-up only. This page carries no certificate.
- Sightline literature
C-value is discussed around 90–120 mm, then geometry and code fix it. This page does not impose it.
Last editorial review: 2026-10-06. Review means the text was checked, not that a project was measured.
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