water-closet arrangements, namely, the pan-closet with D trap. This
arrangement is exceedingly well known: it is a most skilfully devised
piece of apparatus for retaining sewage in the house, and distilling
sewer gas from the same, and it is the cause of probably nine out of
ten of the actual smells perceived in houses, even if it does not (as
some say) give rise to much actual disease.
The soil pipe discharges over a small cesspool at the foot. This is
a very common arrangement. The cesspool is usually dignified by the
name of a dip trap. The percentage of houses showing leaky soil pipes
is 31.
Now, observe that, although our constructor has not ventilated his
soil pipe, he has been careful not to leave the system entirely
without ventilation. On the contrary, by the simple device of leaving
a rain-water pipe untrapped at the foot, he has ventilated the
drains, and also the public sewer, into the back bedroom windows!
This is a quite common arrangement, and frequently results in typhoid
fever.
Next, in order, we may take the case of the discharge pipes from
baths, sinks, basins, and all such appliances. It has been laid down
as a rule by the best sanitary authorities that these appliances
must discharge not into the soil drains, but into the open air over
trapped gullies, as it has been found that this is the only way of
being absolutely certain that no sewer air shall enter the rooms by
the discharge pipes. It is quite true that if a trap be fixed on a
discharge pipe of, say, a sink, the greater part of the sewer air may
be kept back from the house; but traps, however excellent they may
be in _assisting_ to keep out sewer air, are not alone sufficient.
There are several reasons for this. In the first place, there is
the fact that a certain amount of sewer gas will pass through the
water of a trap, or, to speak more strictly, will be absorbed by
the water on one side, and afterwards given off on the other side.
It is true that in the case of a well-ventilated drain this amount
will be infinitesimal, and might even be disregarded, but there are
other causes for the uncertainty of a trap. If the appliance, on the
discharge pipe of which it is, be disused for a long time, there is
the possibility that the water in the trap may dry. In this case,
of course, there is no further security. Besides this, however,
there is an action known as siphonage, in which the rush of water
through a pipe carries with it the water which ought to remain in
the trap and form a seal. In Fig. 21 are shown several different
ways of connecting sinks, &c., with drains. The discharge pipe often
carries an apology for a trap, in the form of a little apparatus
called a bell trap. But, as a matter of fact, it is the commonest
thing possible to find the bell trap lying on the sink. It has been
lifted out of its place to let the water run down the waste pipe more
quickly. It is no unusual thing to go into the scullery of a house,
and to find the discharge pipe of the sink quite open, and a blast of
sewer air issuing from it which will extinguish a candle.
In other cases the sink has an arrangement which is called a grease
trap, but is, in reality, nothing more nor less than a particularly
foul cesspool. It calls for little remark. The pipe from the sink
dips into the foul water to make a trap. In many cases, the pipe does
not dip into the water; but there is a bell at the top. Sometimes the
drain is at various places made up with bricks. This is a very common
thing to find in houses. The bricks are used to save the trouble of
getting special junction bends, &c. The other sinks and baths in the
house are shown as discharging into the closet traps. This is a very
common and objectionable arrangement. Sixty-eight per cent. of houses
examined show the defects last mentioned; that is to say, the sinks,
baths, or fixed basins are connected with the drain or soil pipe,
a trap of some kind generally, but not always, forming a partial
security against sewer gas.
As mentioned before, the only ventilation in this case is such as
will permit the issuing sewer gas to find its way into the house. It
is by no means unusual to find no provision at all for ventilation,
or to find the ventilating pipes so small that they are totally
useless. In more cases than one, Burton found the soil pipe carried
up as a rain-water pipe into the attics, where it received rain-water
from two gutters, one from each side of the roof, and discharged all
the sewer gas which escaped by it. Generally, the drinking-water
cisterns are situated in such attics.
It may be noted, in the other drawing (Fig. 21), that a trap is fixed
on the main drain, which will keep back almost all sewer gas, and
that ventilating pipes are so arranged that a constant circulation of
fresh air exists through the whole drainage system, and will carry
away with it any little sewer gas which passes through the trapping
water.
The most perfect water-supply arrangement does not necessitate
the existence of cisterns in the house at all. This is beside the
mark, for the reason that in London, to which Burton confines his
remarks, the supply of water to the greater portion of the town is
intermittent, so that cisterns are a necessity.
Water, even in London, is almost always delivered in a sufficiently
pure state to be drunk, but it is a very common thing for it to be
contaminated in the cisterns. Even if there be no actual disease
germs carried into the water, there is liability of deterioration
from the mere fact of a large quantity of water being stored for a
long time before use. If the cisterns are of so great size as to hold
as much water as is used in, say, three or four days, it follows
that all water drawn has remained in these cisterns for an average
time of several days. This is by no means likely to improve its
quality, but, on the contrary, if it does nothing else, it renders
it flat. There are far more dangerous causes of contamination than
this, however. The commonest of these is to be found in direct
communication between the drains and the cisterns through the
overflow pipes of the latter. This is shown in Fig. 20. It will be
seen that there is a trap on the pipe by way of protection against
the sewer gas. This is a by no means uncommon arrangement; but, as
will be readily understood, such a trap is absolutely of no good.
An overflow pipe to a cistern is merely an appliance to be put in
use in case of an emergency; that is, in case of derangement of the
ball valve through which the water enters. As a matter of fact,
an overflow may not occur from year’s end to year’s end--probably
does not--and, as a consequence, the trap soon becomes dry, and the
temporary security afforded by it is lost. In 37 per cent. of houses
inspected, Burton found direct communication between the drain or
soil pipes and the drinking-water cisterns.
Another means by which the water of cisterns is contaminated is by
their being placed in improper positions. Quite frequently, a cistern
in which drinking-water is stored, is situated in, or even under the
floor of a w.c. Burton has known more than one case in which the drip
tray under a closet actually discharged into a cistern.
It is even possible for contamination of water to occur through the
mere fact that a water-closet is supplied from a certain cistern.
With a water-closet supplied by the modern regulator-valve apparatus,
this is most unlikely; but it will be readily seen how it may occur
with such an arrangement as that shown in Fig. 20, which is common.
Here it will be seen that for each water-closet there is a plug in
the cistern. This plug is so arranged that when it is raised by the
wire which connects it with the water-closet branch, it suddenly
fills what is called a service box, this being a subsidiary cistern
fixed under the body of the main cistern, and in direct communication
with the water-closet. After the water has run out of the service
box, this is free to fill itself with foul gas from the water-closet
by the service pipe, and the next time the plug is lifted this same
foul gas passes into the water, which absorbs a part of it.
There are many other points in the drainage arrangements of a house
which may possibly become causes of danger, such as surface traps
in areas, &c. In speaking of the drain of a house, it has been
considered as a single length of pipe; but it must be remembered that
in any drainage system, except the most simple, there are branch
drains, often many of them, and that these are liable to the same
evils as the main drains, and require the same attention. In fact,
seeing that less water is likely to pour down them, they require more
attention.
Burton concludes his paper with a brief description of the methods in
use for discovering defects in house sanitation.
One thing that is absolutely necessary for such inspection, and
without which it would be quite incomplete, is to open down to the
drain. This should be done at the nearest point to that at which it
leaves the premises. There is no absolute guide to tell where this
point is, but after some experience it is generally possible to hit
upon the spot with very little searching. In the house illustrated in
Figs. 20, 21, it would be under the front area or cellar. The ground
should be entirely removed from the drain for at least two lengths of
pipe. It is also very desirable that a portion of the ground over the
top of the drain should be removed.
We may next take the point of trapping of the main drain and
ventilation of the system. It will be seen that, in the case of the
drawing of the imperfect arrangements, the drain is shown to be in
direct communication with the sewer. The consequence is that any
leakage which may exist in the house drain permits gas not only from
the drain itself, but from the sewer also, to find its way into the
house.
The engineer will now be able to tell much of the state of affairs.
He will see of what size the drain is; he will be able to tell of
what material the joints are made, taking those exposed as samples;
he will, in all probability, find the ground under the pipes soaked
with sewage, and be able at once to say that the drain is in a leaky
and bad condition; he will find whether it is properly supported
on concrete, or has been “tumbled” into the soil; he will be able
readily to discover what is the total fall in the drain from back
to front. At this stage of the proceedings, the drain itself should
not be opened; but, on the contrary, if the taking up of the ground
should have exposed any joints which are evidently leaking, these
should be made temporarily good with clay. The reason is, that it is
desirable, before anything has been disturbed, to test the system for
the purpose of discovering what amount of leakage there is into the
house.
There are various ways of doing this, but the two commonest, which
Burton describes and illustrates, are those known as the “peppermint
test,” and the “smoke test.”
The smell of peppermint is well known, possibly to some of us
unpleasantly well known, but probably its excessive pungency when
in the form of the oil, and when brought into contact with hot
water, is not generally understood. It will readily be believed
that if such an excessively pungent mixture as this be introduced
into the drainage system of a house, even the smallest leakage will
become evident. Suppose the least possible defect to exist in any
joint of any of the pipes, a strong smell of peppermint will be
evident near the defect. The only difficulty is in finding a place
to introduce the peppermint. It will be quite evident that it is no
use to pour it into any of the appliances in the house, as, were
such done, this smell would so rapidly permeate the whole of the
premises, by way of the staircase, passages, &c., that time would
not be allowed to detect the leakages. Some means must be discovered
of getting the peppermint in from the outside. This is not always
possible, but generally it is. In the case illustrated, there would
be no difficulty. The rain-water pipe at the back admirably suits
the purpose. One person gets out on the flat roof, near the top of
the pipe, and provides himself with peppermint, and 4 or 5 gallons
of water, as nearly boiling as possible. Meantime, all doors and
windows are closely shut, and persons are stationed about the house
to observe if the smell expected becomes evident, and to locate, as
far as possible, the point from which it issues. The man on the roof
pours about ½ oz. of the oil down the pipe, and follows it with the
hot water. He need then retreat from the place a little, for the
peppermint-laden steam which will come from the pipe is blinding in
its pungency. As soon as possible, he plugs up the top of the pipe
with a towel, or some such thing, to prevent the occurrence of the
vacuum which would otherwise be in the pipes, and which would tend
to draw air from the house into the pipes instead of from the pipes
into the house at any leakage. It would probably not be a minute
before the people in the house would perceive the smell at various
places. The manipulator of the peppermint must remain perched on the
roof until those inside have had time to make their observations,
otherwise he will infallibly bring the smell with him.
The test described is an excellent one. It is searching, and is
simple in application, but it has one drawback. It is impossible by
means of it exactly to localise a leakage. This drawback does not
apply to the smoke test. A smoke machine is nothing more nor less
than a centrifugal pump attached to a vessel for generating smoke.
The pump pumps smoke out by a pipe, which may be inserted in any pipe
in direct communication with the drain or in an aperture made for the
purpose. The test is, in all respects, similar to the peppermint one,
except that the leakage is not smelt but seen.
After the test has been performed the drain may be opened. This may
be done by breaking into a pipe in front, by breaking off a collar,
or by punching a round hole in the pipe. In any case it will be
possible to judge much of the condition of the drain by the manner
in which water runs through the pipes. If we have discovered that
there is sufficient total fall, we can now see whether or not it
is uniform. We shall, as remarked before, find in six cases out of
every hundred examined that there is total stoppage, that no sewage
whatever leaves the premises, and that consequently it must all be
depositing under the basement.
If the drain, after all tests so far applied, and from what can be
seen of it, appear to be in good condition, it may be further tested
by filling, or attempting to fill it with water. There is probably
not an average of one drain in a thousand in London which would
remain full of water for an hour. For the rest it is necessary to
examine all appliances, to trace the pipes from them, and sometimes
to test these pipes.
The engineer has now completed his inspection, and has but to
consider how he will make the best of a bad job, and put things to
rights. At the beginning of his paper Burton expressed his intention
of confining himself to a description of defects, and said he should
not describe what he considered a perfect system; he, however, points
out one or two of the chief features of the arrangements in the house
which he calls well drained.
[Illustration: 22. Disconnecting Chamber.]
Most notable, probably, is the small size and sharp fall of the
drain pipes. Further than this, it will be seen that the drain is
disconnected from the sewer by a trap, and that it is accessible for
inspection throughout, simply by lifting certain iron covers (Fig.
22). A close examination would show that every foot of drain pipe
and discharge pipe is so ventilated, that there will be a current of
air through it; that no appliance discharges into the drain direct,
but that there is an atmospheric disconnection in every case; that
air from discharge pipes of sinks, &c., is all trapped from the
house; that there is separate water supply for closets, and for other
purposes; and that no cistern has any connection with the drains.
Further will be noticed, the difference in construction of the
closets, &c.
The foregoing abstract of Burton’s paper is replete with valuable
information. One obvious inference to be drawn from it is that where
the occupant of a dwelling has serious doubts as to its sanitary
conditions and cannot rely on his own observation for ascertaining
the facts, he should forthwith engage the services of a specialist
like the author of the paper to aid him in coming to a decision.
One of the most instructive lectures on house sanitation was
that delivered by Prof. Corfield at the Parkes Museum in 1883.
He considers that the best plan in the examination of a house is
to begin at the top of it, proceeding downwards, and noting the
different mistakes that are likely to be made in the sanitary
arrangements in various parts of the house. Following out this idea,
we will deal with each item in descending order.
_Rain-water._--The first thing which we must consider is that we have
to get rid of the water that falls on the roof. The water from the
gutter in front of the house may be disposed of in one of several
ways. It may be conducted by a pipe outside of the house down the
front into the area; or it may be conducted by a gutter through the
roof, or, perhaps, through one of the rooms in the upper story into
a gutter, over the middle of the house, between two parts of the
roof, and down the middle of the house by a pipe into the drain; or
it may be conducted direct from the gutter by a pipe, not outside the
house, but inside the house, passing down through one or two stories,
inside the rooms, perhaps through the best bedroom in front of the
house, through the drawing-room, carefully hidden by some casing
made to look like an ornament, through the dining-room and kitchen
into the drain in the basement. Smells having been perceived in
different parts of the rooms, especially in the bedrooms, various
sanitary arrangements may be improved, and even made as perfect
as they can be, by a kind of amateur tinkering prevalent nowadays
in sanitary matters; and yet this defect which is so exceedingly
serious, which is known to give rise to serious disease, is entirely
overlooked--perhaps for years. The same is the case when the
rain-water is carried in a gutter through the roof into a gutter
between the two roofs in the middle of the house, and down by a
rain-water pipe inside the house. In such cases similar disasters may
occur.
But there is an additional danger from the fact that these inside
gutters are in themselves most pernicious things. Soot and rotten
leaves collect in them, and air blows through them into the house;
and especially when these gutters are under the floors of bedrooms,
this foul air is often the cause of illnesses which occur in these
rooms. Even gutters which are not themselves directly connected with
the drains, and which are open at both ends, but in which decayed
leaves and soot accumulate and give off foul air into the rooms, may
be the cause of sore throats.
Another plan to dispose of the rain-water is to carry it in a gutter
right through the house to the back (the gutter may pass through the
roof or the garrets), and the same remark applies to this method of
construction as to those just described, except that it does not
imply necessarily a defective pipe running down to the drain.
Well, then, the rain-water from the roof should be conducted by pipes
placed outside the house; and there is no reason why this should
not be always the case. If these pipes are not disconnected from
the drains below, but are connected with them either directly, or
even indirectly (with a bend in the pipe to hold water), in either
instance cases of disease will arise in the rooms, the windows of
which are near the rain-water pipes.
It is exceedingly difficult to persuade people upon this point; but
such is the case. When the rain-water pipes starting from the top of
the house below the bedroom windows, and frequently behind parapets,
so that any air that comes out at the top comes out exactly close to
the bedroom windows, and when these pipes come down straight into the
drains and so ventilate the drains, foul air from the drains gets
into the house, and disease is the result. But it is more difficult
to make people understand that even when these rain-water pipes are
trapped at the foot they are almost as dangerous as the untrapped
ones, because foul air from the drains will pass gradually through
the water in the traps into the pipes, so that these pipes are always
filled with foul air and contain gases that have come from the drains.
As soon as it rains, water passes down, and the air of these pipes is
displaced, comes out at the top, and so if these tops are near the
windows of rooms, cases of disease will happen in those rooms.
The rain-water pipes ought to discharge on to the surface of the
areas, where there ought to be siphon gullies connected with the
drains.
_Ventilating Pipes._--While on the roof we can look around and
observe the ventilating pipes: 1st, whether there are any or not;
2nd, of what size; 3rd, whether they have cowls or not; and 4th, in
what positions they are. If we observe that they end at the top, near
to chimneys, we shall see that there is liability, on account of the
down draught, of the foul air from these ventilating pipes passing
down the chimneys.
Chimneys often have down draughts, and if ventilating pipes are
placed near them, the foul air may pass down into the rooms. If, on
the other hand, although not ending near the tops of the chimneys,
they are placed close to the chimneys or to walls so that their tops
are sheltered, they will not act properly, and they ought to _be
carried above the ridge_ of the roof, and end away from walls or
chimneys. The same rule applies to chimney tops, they should not be
sheltered by higher buildings.
_Cistern._--The first thing we come to inside or just below the roof
(or perhaps on the roof), is the cistern.
The first point to observe is the material of which it is made. Lead
cisterns (and so, too, galvanised iron cisterns) are affected by
certain kinds of water; and it is important, in certain places, that
cisterns should be used which are not capable of being affected by
the water. Galvanised iron cisterns cause certain forms of poisoning
with some waters. However, as a matter of fact, both lead and
galvanised iron cisterns are used enormously, without any serious
results following from their use.
A cistern is provided with an overflow and waste pipe. If the cistern
is on the roof you would think it the natural thing that the overflow
pipe should discharge on to the roof or leads, or into an open head;
but, as a matter of fact, it is generally not the case. (By an
“overflow” pipe is meant a pipe from the top, and by a “waste” pipe
a pipe starting above the level of the water and passing through the
bottom of the cistern.)
Overflow pipes were not in fashion at all until recently. The fashion
was to have a waste pipe, and the most convenient place to take
that into was some pipe passing down the house, which might be a
rain-water pipe, but more frequently it was the pipe into which the
water-closets discharged, which is called the “soil” pipe.
When this is the case the waste pipe of the drinking-water cistern
becomes the ventilator of the pipe into which the water-closets
discharge; and so in nine cases out of ten the ventilator of the
house drain and of the sewer under the street, and, indeed, one of
the ventilators of the main sewer. So foul air passes continually
by means of this ventilator into the drinking-water cistern at
the top of the house. Now foul air in sewers and drains contains
matters in suspension, and often the poisons of certain diseases,
such as typhoid fever; it gains access to the water in the cistern
and contaminates it, and the main cause of typhoid fever in London
and many other large towns is the connection of the drinking-water
cisterns with the drains by means of the waste pipes.