ANTI-TERMITE TREATMENT
Sub-terranean termites are responsible for most of the
termite damage in buildings. Typically, they form nests or colonies
underground. In the soil near ground level in a stump or other suitable piece
of timber in a conical or dome shaped mound. The termites find access to the
super-structure of the building either through the timber buried in the ground
or by means of mud shelter tubes constructed over unprotected foundations.
Termite control in existing as well as new building
structures is very important as the damage likely to be caused by the termites
to wooden members of building and other household article like furniture,
clothing, stationery etc. is considerable. Anti-termite treatment can be either
during the time of construction i.e. pre- constructional chemical treatment or
after the building has been constructed i.e. treatment for existing building.
Prevention of the termite from reaching the super-structure
of the building and its contents can be achieved by creating a chemical barrier
between the ground, from where the termites come and other contents of the
building which may form food for the termites. This is achieved by treating the
soil
beneath the building and around the foundation with a
suitable insecticide.
MATERLS
The following chemicals in water emulsion to achieve the
percentage concentration specified against each chemical shall be used:
• Chlorphriphos
emulsifiable concentrate of 20% .
Anti-termite treatment chemical is available in concentrated
form in the market and concentration is indicated on the sealed containers. To
achieve the specified percentage of concentration, Chemical should be diluted
with water in required quantity before it is used. Graduated containers shall
be used for dilution of chemical with water in the required proportion to
achieve the desired percentage of concentration. For example, to dilute
chemical of
20% concentration. 19 parts of water shall be added to one
part of chemical for achieving 1% concentration.
Engineer-in-Charge shall procure the chemical of required
concentration in sealed original containers directly from the reputed and
authorized dealers, chemical shall be kept in the custody of the Engineer-
in-Charge or his authorized representatives and issued for use to meet the
day’s requirements. Empty containers after washing and concentrated chemical
left unused at the end of the day’s work shall be returned to the
Engineer-in-Charge or his authorized representative.
ANTI - TERMITE TREATMENT: POST-CONSTRUCTION TREATMENT
• Chemicals
: Any one of the following chemicals conforming to relevant Indian Standards in
water emulsion may be used for soil treatment in order to protect a building
from termite attack.
Chemical with Percent Relevant
Indian Standards (Active ingredient) Concentration by weight
Chlorpyrifos 20EC IS
8944 1.0
These chemicals are available in concentrated form in the
market and concentration is indicated on the sealed containers. To achieve the
specified percentage of concentration, chemicals should be diluted with water
in required quantity before it is used. Graduated containers shall be used for
dilution of chemicals with water in the required proportion to achieve the
desired percentage of concentration.
For example, to dilute chemical of 20% concentration, 19
parts of water shall be added to one part of chemical for achieving 1%
concentration. Oil or kerosene based solution of chlorpyrifos 20 EC or Lindane
20 EC,1.0 percent (by weight) concentration is useful for treatment of wood.
Engineer-in-charge shall procure the chemical of required concentration in
sealed original containers directly from the reputed and authorized
representative. Chemical shall be kept in the custody of the Engineer-
in-charge or his authorized representatives and issued for use to meet the
day’s requirements. Empty containers after washing and concentrated chemical
left unused at the end of the day’s work shall be returned to the
Engineer-in-charge or his authorized representative.
• Safety
Precautions : Chemical used for anti-termite treatment are insecticides with a
persistent action and are highly poisonous. This chemical can have an adverse
effect upon health when absorbed through the skin, inhaled as vapours or spray
mists or swallowed.
The containers having
emulsifiable concentrates shall
be clearly labelled and kept
securely closed in stores so that children or pet cannot get at them. Storage and mixing of
concentrates shall not be done near any fire source or flame. Persons carrying
out chemical soil treatments should familiarize themselves and exercise due
care when handling the chemicals whether in concentrated or in diluted form.
After handling the concentrates or dilute emulsion, worker shall wash
themselves with soap and water and wear clean clothing especially before eating
and smoking. In the event of severe contamination, clothing shall be removed at
once and the skin washed with soap and water. If chemical has splashed into the
eyes, they shall be flushed with plenty of soap and water and immediate medical
attention shall be sought.
The use of chemical shall be avoided where there is any risk
of wells or other water supplies becoming contaminated.
TREATMENT PROCESS
A. Once the
termites have an ingress into the building, they keep on multiplying and
destroy the wooden and cellulosic materials, and as such it becomes essential
to take measures for protection against
termites. Anti termite measures described below are necessary for the
eradication and control of termites in existing building. To facilitate proper
penetrations of chemical in to the surface to be treated, hand operated
pressure pump shall be used. To have proper check for uniform penetration of
chemical, graduated containers shall be used. Proper check should be kept so
that the specified quantity of chemical is used for the required area during
the operation. Chemical treatment for the eradication and control of
sub- terranean termites in existing building shall be done as per IS 6313 (Part
III). Treatment shall be got done only from the approved specialized agencies using
the chemical procured directly by the Engineer-in-Charge from reputed and
authorized dealers.
B. Treatment
along outside of foundations: The soil
in contact with the external wall of the building shall be treated with
chemical emulsion at the rate of 7.5 litres per square metre of vertical
surface of the sub-structure to a depth of 300 mm. To facilitate this
treatment, a shallow channel shall be excavated along and close to the wall
face. The chemical emulsion shall be directed towards the wall at 1.75 litres
per running metre of the channel. Rodding with 12 mm diameter mild steel rods
at 150 mm apart shall be done in the channel. If necessary, for uniform
dispersal of the chemical to 300 mm depth from the ground level. The balance
chemical of 0.5 litre per running metre shall then be used to treat the
backfill earth as it is returned to the channel directing the spray towards the
wall surface. If there is
a concrete or
masonry apron around
the building, approximately 12 mm diameter holes shall
be drilled as
close as possible to the plinth wall about 300 mm apart, deep
enough to reach the soil below and the chemical emulsion pumped into these holes to soak the soil below at
the rate of 2.25 litres per linear metre.
In soils which do not
allow percolation of chemicals to desired
depth, the uniform disposal of the chemical to a depth of 300
mm shall be obtained by suitably modifying the mode of treatment depending on site condition.
In case of RCC foundations the soil (backfill) in contact
with the column sides and plinth
beams along with external
perimeter of the
building shall be treated with
chemical emulsion at the rate of 7.5 litres/sqm. of the
vertical surface of the structure. To facilitate this treatment, trenches shall
be excavated equal to the width of the
shovel exposing the sides of the
column and plinth beams
up to a depth of 300 mm or up to the bottom of the plinth beams, if this
level is less than 300 mm. The chemical emulsion shall be sprayed on the
backfill earth as it is returned into the trench directing the spray against
the concrete surface of the beam or column as the case may be.
C. Treatment
of Soil under Floors: The points where
the termites are likely to seek
entry through the floor are the cracks at the following
locations:
1. At the
junction of the floor and walls as
result of shrinkage of the concrete;
2. On the
floor surface owing to construction
defects;
3. At
construction joints in a concrete
floor, cracks in sections;
D. Expansion
joints in the floor : Chemical treatment shall be provided in the plinth area
of ground floor of the structure,
wherever such cracks are noticed
by drilling 12 mm holes at the junction of floor
and walls along the
cracks on the floor and along the
construction and expansion joints at the interval of 300 mm to reach the soil below. Chemical emulsion shall be squirted into these
holes using a hand
operated pressure pump to
soak the
soil below until refusal or up to
a maximum of one litre per hole. The holes shall then
be sealed properly
with cement mortar
1:2 (1 cement: 2 coarse
sand) finished to match the
existing floors. The cement mortar applied shall
be cured for
at least 10 days as
per instruction of Engineer-in-charge.
E. Treatment
of Voids in Masonry : The movement of
termites through the masonry wall may be
arrested by drilling holes in masonry
wall at plinth level and squirting
chemical emulsions into the holes to
soak the masonry. The holes shall be drilled at an angle of 45 degree from both
sides of the plinth wall
at 300 mm intervals and emulsion squirted through
these holes to
soak the masonry
using a hand operated pump. This treatment shall also
be extended to internal walls having
foundations in the
soil. Holes shall
also be drilled
at wall corners and
where door and
window frames are
embedded in the masonry or
floor at ground. Emulsion shall be
squirted through the holes
till refusal or to a maximum of
one litre per hole. Care shall be taken to seal the holes after the
treatment.
Infested wood work
in chaukhats, shelves,
joints, purlins etc.,
in contact with the
floor or the
walls shall be provided with protective treatment by drilling holes
of about 3 mm diameter with a
downward slant to the core of the wood work on the inconspicuous surface of the frame.
These holes should
be at least 150 mm centre to centre
and should cover in entire frame work. Chemicals shall be liberally infused in
these holes. If
the wood is
not protected by paint
or varnish two coats of the chemicals shall be given on all the surfaces
and crevices adjoining the masonry.
