- What is the minimum diameter of a vertical stack serving:-
- normal WC, and
- only a kitchen sink
- If a vertical stack is ventilated by a caged open end, what is the minimum
height this ventilated end needs to be above an opening, such as a window,
in any nearby building? How far away from the opening does the stack have
to be, before this distance no longer applies?
- A stack goes vertically from a 2nd floor flat down to the ground, but has
to divert horizontally for a distance at first floor level before resuming
the vertical drop to the ground. What precautions are needed to avoid the
traps, of the wc, sink, and bath in the first floor flat being "pulled" by
the air pressure from the change in direction?
If the building was 4 storeys high and the stack went from the 3rd floor storey
would the precautions be the same?
- You visit a 3 storey high block of flats. The plumber points out that the
connection from the ground floor flat bath will discharge into the stack at
500mm above the invert of the bend at the foot of the stack. He asks is this
OK? He is unsure if it ought to be 450mm minimum or 750mm minimum? Which dimension
is correct and why?
- A builder of a 3 storey house wants to stop the stack inside the building
with a "Durgo" air inlet valve. Would this be acceptable if the "Durgo" is:-
- in the loft space above the insulated ceiling of the top floor storey;
- in the cupboard below the top floor bathroom hand basin;
- boxed in with an air tight casing in the top floor bathroom; or
- under the eaves of the pitched roof.
Would it make a difference if the stack was at the head of a drain run?
- You visit site and notice that a washbasin in a bedroom has a 32mm diameter
branch pipe which is 3m long from basin to stack. Is this OK? If not what
could be done to easily resolve the problem.
- You visit an industrial unit with 1st floor office. There is an existing
stub stack drain for the ground floor wc. The plumber asks if it is acceptable
to connect a new first floor sink into this stub stack? Give reasons for your
answer.
- You visit a loft conversion where a new shower and washbasin is being installed.
You notice that the shower has a trap with a depth of seal of only 38mm. When
you suggest that it should be 75mm for the shower and 75mm for the washbasin,
the builder argues that there was insufficient space for 75mm and that it
must be OK to use a 38mm trap, or it would not be made that way. Explain why
this is wrong.
- You visit a house and notice that a new sink has the drain pipe discharging
over the gully grating. Is this OK? If not what should have been done and
how can the situation be remedied?
- What is the minimum diameter for an underground drain pipe serving:-
- a washbasin; and
- a wc.
- If an underground drain pipe passes through the wall of a building, what
precautions need to be taken to prevent possible future settlement fracturing
the pipe?
- A new factory building is being erected. There is a long drain run from
the toilet facilities at the rear of the building and the sewer at the front
of the building. If the diameter of the pipe is 100mm what is the minimum
gradient?
A short section between manholes drops steeply at 45 degrees to the horizontal.
Is there a maximum gradient for 100mm dia. pipes?
As the drain run is very long between manholes at what centers should there
be rodding eye access?
If the drain pipe will be 500mm deep at one end and 200mm below the underside
of the concrete floor slab at the other end, what bedding precautions are
necessary to ensure that the pipes will not be damaged by settlement?
- A new UPVC foul drain pipe is to be installed in the access passage between
two semi-detached houses. What bedding should be used? If it is found that
the drain is to go below the foundations would the bedding detail change?
If so to what?
- You visit site and note that UPVC drain pipes are 500mm down from the level
of the ground. Would special precautions be needed to prevent foot trafic
flattening the pipes? What difference would it make if the pipes were below
a road?
- A builder is constructing a manhole at a bend in a 100mm dia clay pipes
drain. The builder asks do "rocker" pipes need to be installed and how far
from the manhole sides should the first joint go? Also asks that as the manhole
is only 950mm deep are step irons required?
- You are asked to witness a water test of a 20m long 100mm diameter drain
run. Stoppers have been put in one manhole and the other manhole filled with
water. The top of the manhole is 450mm diameter. After 5 minutes the water
level has descended in the top of the manhole 4mm. Assuming this rate will
continue for the full 30 minutes would the test be satisfactory?
- A 2 storey house has been constructed with a bathroom suite on the first
floor and you are asked to witness a drain test of the above ground pipework.
On site the plumber claims to have left the air testing equipment at home.
Would you be prepared to accept a water test instead? Give reasons why this
is not acceptable.
Watewater treatment systems and Cesspools, Part H2
- How far from a road should a cesspool be located?
Rainwater drainage, Part H3
- A new 2 storey terrace house is designed to have a 45 degree mono-pitch
roof from back wall to front wall. The front first floor windows are constructed
as dormer windows and the front wall stops at first floor level. The size
of the house plot is 6.0m wide by 8.0m long. The gutter at the front of the
roof is drained by a single 75mm drain pipe. Is this adequate? How wide should
the gutter be?
- A single storey extension is being built at the rear of a 2 storey house.
The builder proposes to let the existing rainwater pipe discharge onto the
new roof where it adjoins the existing building. The new extension roof is
to be provided with a gutter and rain water pipe at the rear of the extension.
Is this acceptable?
- The builder of a rear extension is unable to find an existing gulley leading
to the storm water drain in the road. Instead the builder proposes combining
the rainwater and foulwater pipes in the foulwater manhole. Is this normally
acceptable? Give reasons.
- A very long gutter is being constructed to an industrial building. Should
there be a fall on the gutter?
- The Water Authority have asked that you inform clients that they require
the use of soakaways wherever practical to avoid the overloading of their
surface-water sewers. A builder is doing an extension and wishes to discuss
the construction of the soakaway. How far from the nearest building should
a soakaway be located? Approximately how large should a soakaway be for a
typical house extension's roof?
Solid Waste Storage,
- A new 4 storey block of flats is being built. Should a refuse chute be provided
to a shared waste container?
- How far should refuse containers be positioned from where there is vehicle
access? From where to where do you measure to ascertain if this is too far
for householders to be expected to carry refuse?
- If a room is to be provided in the ground floor for the storage of refuse,
can it open off the entrance hall leading to the common stairs? Give reasons.
(Also look at section 6 of Approved Document B1).
Building Regulations
- An office building is to be converted into flats. You consider that the
existing facilities for storage of refuse are inadequate. Under which Building
Regulations would you require that there must be adequate solid waste storage
for the flats?
- An office building is being converted into flats. The drains are not being
altered as the existing offices had a kitchen, showeroom, and wc on each floor.
Are you able to require under the building regulations that the adequacy of
the drains be checked for the likely increase in useage?
- It is proposed that a New house use the existing drain runs to the sewer
of a neighbouring house. Under what building regulations would you require
that a video survey and drain test be done of the existing drains to demonstrate
adequacy?
Building Act 1984
- You are telephoned in the middle of the night and informed that the Police
have reported falls of Masonry into the road from a building. When you arrive
at the property you notice that part of the projecting cornice at the top
of the buidings front wall has fallen into the street. It looks as if more
might come down at any time on to any passing pedestrian in the street. Under
what Section of the Building Act could you call out the Council's emergency
contractor to remove the danger? Do you have to find the owner of the building
first to get their permission? If you were employed by an Inner
London Borough would the legislation be different? If so what would
be the practical difference?
Click here to Return
to top of page
The Inner London Boroughs are:-
- The City of London
- The City of Westminster
- The Royal Borough of Kensington & Chelsea
- Hammersmith & Fulham
- Wandsworth
- Lambeth
- Southwark
- Lewisham
- Greenwich
- Tower Hamlets
- Hackney
- Islington
- Camden
Click here to Contact
details of Inner London Boroughs
Updated on 3rd March 2001 by Robert
Hunter-Jones MSc CEng MICE MIStructE FRICS
Please click on underlined name to send your E-Mail comments on these web
pages.
