PRM SEM 01 - 05. Building Code Detail for Designers

Question 1

D1: What is an Accessible Route?

Answer 1

“Accessible route” is an access route that a disabled person, especially in a wheelchair, can use.

But also useful for very young, very old, heavily burdened, sick, injured, disabled, blind etc.

Remember accessibility isn’t just for customers, its for staff too.

Often signposted with wheelchair symbol in commercial buildings eg restaurants, malls.

Every building must be accessible except individual houses, outbuildings, ancillary buildings,
industrial buildings where 10 or less people are employed.

Even existing buildings must comply “as near as practicable”.

You have “existing use rights” until you alter a building or it’s use / activity. This can make alterations and retrofits particularly difficult, but the Council is strict on accessibility.

Question 2

D1: Car Parking

Answer 2

No real accepted national standard; refer to the Council (Territorial Authority’s) District Plan for their requirements: how many car parks per activity and the dimensions.

Concept of percentile rather than “average”: carparks are not designed to suit the average car but rather 90% or 95% of those on the road (it’s unrealistic to have carparks big enough to
accommodate 100% of vehicles on the road eg hummers, limos, hearse)

Typical size and angle of carparks, vehicle turning circles, accessible car parks (about one and a
half times usual width, close to entry) can be found in the Council’s District Plan (or is it Unitary Plan now?). Auckland City’s is available in the library and on line at
http://www.aucklandcity.govt.nz/council/documents/district/text.asp
Private carparks you are familiar with in home or workplace can be tighter (90%ile) than public
carparks in malls (95%ile).
Generally all vehicles must be able to turn on site without reversing onto road.
Single houses generally require two carparks.
You may also need a cart dock / loading bay for light trucks.

Question 3

D1: Accessible Route Dims

Answer 3

Paths / corridors in buildings other than houses: 1200mm (1.2m) wide minimum (compared to
900mm typical in NZ house). 810mm wide door leafs to give 760mm clear openings between jambs.
Be more generous in multi-storey buildings to allow for moving furniture (and coffins!). Avoid
projections along route eg columns, opening windows, fire extinguishers / hose-reels etc

Question 4

D1:Slip resistance and trip avoidance

Answer 4

The Code won’t allow certain flooring materials in certain locations. Consider whether material is
level, on slope, dry or wet (eg outside, lobby areas) then refer to Table 2 Clause D1: These materials are unacceptable when wet even though level: smooth timber decking, smooth finished concrete, painted concrete, some vinyls, some stone finishes (polished marble), some ceramic tiles!
Apart from actual stairs / steps no level changes of more than 20mm eg at door thresholds. Use
contrasting colours and textures at level changes eg stair nosing’s

Question 5

D1:Accessible ramps:

Answer 5

Width 1200mm (1.2m). Pitch should be 1 in 12 (1m rise requires 12m long ramp), you also need
landings (every 750mm of rise). Other ramps, service ramps can be steeper. Ramps need kerbs or handrails.

Question 6

D1:Stairs

Answer 6

Dimensionally very sensitive, 10mm is a lot!
Typically 280mm minimum tread (300 ideal), 190 maximum rise (175 – 185 ideal)
No “open risers”, no gaps larger than 100mm. Rises should be angled leaning forward or have an
overhanging nose.
Landings: maximum rise in a private house: 4m, elsewhere: 2.5m then need landing.
So you don’t need a landing between floors in a house, you do in other buildings.
Spiral stairs must be wide to avoid slipping down centre. Can’t have too many “winders” at corners.
Handrail: must be continuous, graspable, uninterupted and between 900mm-1000mm height… and obey balustrade rules.

Question 7

D1:Lifts

Answer 7

Clause D1.3.4(c) tells you when you need a lift eg when a two storey building has 40 people on
upper floor, or when any upper floor is reception area of bank, Council, health care centre etc.

Don’t confuse this with general accessibility rules: a ground floor or single story “split level” still needs to be fully accessible too eg shop, restaurant so will need small lift or ramp for any step up over 20mm!
Councils are very strict on this: see the handout news item.

Lifts are of two types: hoist with pulleys, cables and motor at top in lift housing and a pit at bottom, or hydraulic with a pit and machine room at bottom (limited to six stories).
Both are normally enclosed by concrete or block shafts, but can be enclosed by glass or completely exposed.

Question 8

D1:Counters

Answer 8

Even public reception and shop counters must have a low accessible portion.

Question 9

D1:Balustrades

Answer 9

Look at Oratia rules for pool. Need balustrade when potential fall is over a metre, or a pool is over 400mm deep (but swimming
pool fences aren’t in Clause F4, they are in the Fencing of Swimming Pools Act).
Usually 1000 high. Must be solid or glass or fine mesh or verticals, with no horizontals (‘toeholds”) between 150mm and 760mm above floor level (unless they have veeery narrow gaps). Opening windows with sill below 750mm minimum need a barrier in front or a device restricting the opening.

Question 10

G1: What determines how many toilets are needed?

Answer 10

The tables tell you how many toilets you need: related to use of building and maximum number of
occupants.

Cafes, bars, restaurants, malls, offices, institutions must provide toilets for customers / visitors.
Shops / takeaways don’t have to, but must provide staff toilet (but this can be a distance away eg in malls, staff shut shops and head for main toilets)

Consider if you want staff and customers sharing toilets eg not a good idea in a restaurant.
Consider the distribution around the building rather than one big group, consider peak time use (eg halftime at the theatre or a sports game).

Question 11

G1: Male, Female, Unisex Toilets

Answer 11

Toilets can be separate for males and females, or unisex, or a combination.

Code encourages you to make all your toilets unisex; more efficient in high-rise offices.

Most people feel they wouldn’t like it. But disabled people and their helpers, parents with kids, old couples prefer it and it’s more flexible for all users. But consider whether this is appropriate eg in bars? Toilets are also clubrooms for the male and female tribes!

Question 12

G1: Toilets In Houses

Answer 12

In housing only need one door between toilet and kitchen / living area.

Elsewhere need visual privacy and an “airlock” space called a “lobby”, separately ventilated. A hall counts as a lobby.

Question 13

G1: Same Sex Toilets

Answer 13

In same sex toilets need cubicle screens around toilet pans, can have gaps top and bottom. Urinals and wash hand basins can be open.

Question 14

G1: Unisex Toilets

Answer 14

In unisex toilets, cubicles must have full height walls with no gaps, to give complete privacy. No
urinals permitted anywhere, cubicles must contain their own wash hand basin and a sanitary towel disposal unit.

Question 15

G1: Toilet Expense

Answer 15

Unisex is more expensive per cubicle but you save on total cubicle numbers and lobbies, and save floor area in office and retail space. There is a slow trend to unisex in small and medium size
projects, but having basins in cubicles slows down use.

Question 16

G1: Accesible Toilets

Answer 16

At least one of your toilets must be accessible. Accessible toilet can be unisex but can’t go through male or female area to get to it.

Refer to figure on G1:

1.9m x 1.6m min. Note pan diagonally opposite door. Note door needs 760mm clear opening and slides or opens outwards. Note wheelchair “park” next to pan, note grab rail. Note pans slightly higher than normal and wheelchair needs to get under wash hand basin. Toilets must be separately ventilated from lobby and building.

Question 17

C1-6: Fire Protection and Egress

Answer 17

Single residential dwellings are the exception to most of these rules but generally:

Most buildings need at least two ways out (called “egress”) meaning two stairways for most buildings over a storey. People generally follow an “open path” for approx 10-20m (eg inside a room) to a point where they have a choice of two ways out (eg a corridor with a stairwell at each end). Your studios are a typical example. They then follow a “protected “ or “safe path” (eg smoke stop doors, fire rated walls and doors). Our stair wells are a typical example.

External fire escapes such as ladders are not legal.

Question 18

Fire: Places of Public Assembly

Answer 18

Places of public assembly (eg halls, theatres) are very constrained by these rules and so they are
generally one storey buildings.

Smoke stop doors stop smoke spreading throughout a building. They must have vision panels to
allow view through.

Question 19

Fire: Smoke Stop Doors

Answer 19

Smoke stop doors stop smoke spreading throughout a building. They must have vision panels to
allow view through.

Doors must remain shut and have closers unless held open by magnetic hooks connected to alarm systems that will shut them in emergencies.

Doors open in the direction of egress, with the flow out, not against.

Fire rated walls and doors are made of materials that stop flames burning through.

Ratings vary from 30 minutes to 4 hours, expressed in the form 90/90/90 for example (90 minutes).
Structural steel work is often wrapped in a fire rated material.
All materials have a “spread of flame index” so some materials cant be used in certain situations.
Limitations on extent of windows, external glass especially as building gets close to boundary. Glass can be fire rated.

Question 20

Fire: Sprinklers

Answer 20

Sprinklers greatly simplify fire safety and design issues but are expensive.

Question 21

Fire: Equipment

Answer 21

All buildings (except houses) need illuminated exit signs, fire extinguishers, fire hose reels, fire
alarms, call points (MCPs). Even new houses must have Type 1 smoke alarms.

Buildings have a fire alarm panel outside on the street and “risers” (large pipes) for firefighters to
pump water upstairs (the hydrant ends are visible in our stair wells).

It is very common to engage a fire engineer consultant to ensure Code compliance and produce a Fire Safety Summary, a report that demonstrates compliance.

Question 22

G2 Laundering and G3 Food Preparation

Answer 22

May be required for certain designs

Question 23

Accessibility Standards

Answer 23

For more specific and useful information on accessibility see NZ Standard 4121:2001 Design for
Access and Mobility. Following this standard is one way of complying with the Building Code but is often stricter than the Code’s Acceptable Solutions. But it is good practice rather than just the minimum.
There are architects and consultants who specialise in this kind of work particularly for the disabled.