Water Related Diseases

In underdeveloped countries, a large portion of the population is depended on untreated water for drinking purposes. Every year about 30 millions peoples die in the world because of sanitation problems. Studies have shown that improving the quality of water supplying and sanitation reduces the mortality rate. Typhoid, Cholera and malaria are the most common water-related diseases but they lead to most deaths in the world.

Water Related Diseases

Water-related diseases are classified into four types. They are:

Types of Diseases

1. Water-Borne Diseases

The diseases caused due to the consumption of the drinking water contaminated by the human or animal excrete which contain pathogenic micro-organisms are known as water borne diseases.

They are – Cholera, Typhoid, Dysentry, etc.

2. Water-Based Diseases

These diseases are caused due to the contact with dirty water transmitted through aquatic animals(i.e. fishes) and caused by aquatic organisms that spread a part of their life cycle in water. They are guinea, worm, snail, schistosomiasis, etc.

3. Water Vector Diseases

These diseases are transmitted through the biting of mosquitoes. Vector like mosquitoes transfer parasites( virus, bacteria, protozoa, worms, etc) in the human body. Some diseases of this group are malaria, yellow fever, dengue, etc.

4. Water Washed Diseases

The diseases that are caused due to the lack of personal hygiene. When there is the scarcity of fresh and good water for washing hands or body; infection diseases are transmitted. These diseases are scabies, trachoma( eye inflammation), leprosy fungal infection, etc.

Water Related Diseases

Prevention Methods

1. Drink properly treated water. There are many ways of water treating like the boiling of water, chlorination, Bromine treatment, silver treatment, filtration, ozone treatment, iodine treatment, etc.

2. Take care of personal hygiene. Using bad water to clean body and washing hands leads to more serious problems. So, good water is required for both consumption and external use also.

3. Managing and maintaining good environment to reduce pollution and water-related diseases.

Plastering

Plastering is the process of covering rough surfaces of walls, columns, ceilings and other building components with a thin coat of plaster matters to form a smooth and durable surface. The coating of walls, ceilings, columns, etc with mortar is called plastering.

Plastering on the externally exposed surface is called rendering.

plastering

Objective of Plastering

  • To provide a smooth and finished surface.
  • To give a decorative appearance.
  • To protect the surfaces against atmospheric effects.
  • To resist chemical actions.
  • To cover defects in the structure.
  • To make surface waterproof and durable.

Requirements for good plaster

The plaster material should fulfil the following requirement:

  • It should be hard and durable.
  • It should remain on the surface of the wall and column and protect from chemical attacks and weather.
  • It should have good workability.
  • It should have high strength and durability.
  • It should be cheap and should easily available.
  • It should protect from penetration of nature.

Tools used

  • Trowel
  • Metal float( wooden flat / claying float)
  • Plumb Bob
  • Spirit level

Types of Plastering

There are two types of plastering work that are generally used; based on binding material.

1.Lime Plastering

When lime is mixed with the sand in the presence of the proper quantity of water, it is called lime mortar/ lime plaster. And the process of covering the surface of the walls and columns by using lime plaster is called lime plastering.

Plastering may be single coated or multi-coated. The proportion of lime and sand for lime plastering is generally taken as 1:3 to 1:4.

2.Cement Plastering

When cement and sand are mixed with the proper quantity of water; cement plaster is formed. And the process of co0vering the surfaces by cement plaster is called cement plastering. The generally used mixed proportion of cement and sand for cement plaster are 1: 4, 1:5 and 1:6.

Internal plaster     –      1:6 or 1:5

External plaster    –      1:4

Ceiling plaster       –      1:3

The grade for cement plaster

Grade NameMortar Mix (by Loose Volume)Compressive Strength at 28 days (in N/mm2)
CementSand
MM 0.7180.7   to 1.5
MM 1.5171.5 to 2.0
MM 3163.0 to 5.0
MM 5155.0 to 7.5
MM 7.5147.5 to above

 

Steps for plastering

  1. All joints on faces are raked out by pointing tools.
  2. All the base mortar and dust are brushed and the wall is washed and kept wet for a few hours.
  3. Joints are filled with lime or cement mortar with the help of a trowel.
  4.  The mortar is well pressed into the joints to make solid contact with old mortars in joints.
  5. Finish pointing is kept wet for about 4 days for lime pointing and 10 days for cement pointing.
  6. The mortar is applied throughout the whole surface and levelled by the float.

 

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Curing of concrete

” The process of application of water over the surface is called curing.” Curing may be carried out over the plastered surface or concrete surface. It is done to keep the surface damp after concreting. Curing of concrete provides required water to the cement for the chemical reaction to make concrete hard and strong.

The strength of concrete increases more rapidly in initial stages but after a few days; strength of concrete increases slowly. Generally, 14 days of curing work are required for concreting work.

Curing is not only the application of water over the concrete /  plastered surface only; preventing the loss of moisture is also the type of curing. Two different ways of curing are: 

  1. Application of water to the surface
    E.g. Spraying, ponding, immersion, damp sand, etc.
  2. Preventing the loss of moisture
    E.g. Continuous wetting the surface, using different compounds, etc.

Methods of curing of concrete

Different methods of curing are:

1.Spraying

-Water is sprayed to the concrete surface by the use of different spraying tools and pipes.

-It is suitable for curing vertical surface of concrete-like walls, pillars, etc.

curing of concrete-Reinforced Cement Concrete

2. Wet Curing

-The main aim of wet curing is to prevent moisture loss from the surface.

– Wet curing is done by the use of jute bag, wet sand, etc. 

– This method is suitable for a hot climate.

curing of concrete

3. Ponding

–  In this method, small ponds are made and water is filled on it. 

– It is best for horizontal curing of concrete.

ponding

4. Immersion

– To immerse the concrete of small-size into a water tank; this method is used.

– It is best for separate small concrete elements like the cover of the tank ( concrete cover).

curing of concrete

Lack of curing of concrete

Lack of curing leads to the following:

  1. Cracks of concrete and plasters.
  2. When the paint is applied to the surface which is not cured properly, it leads to non-uniformness, non-smoothness and aligatering of paint. 
  3. Efficiency is decreased by nearly 50 %.

Staircase

1.1: Introduction

      A staircase is a means of providing access from the one-floor level to another. It is a means for vertical circulation. Modern stairs with their handrails are designed with the main emphasis. Space/room for housing stairs is called staircase or the room or enclosure of the building where the stair is located is known as the staircase.

staircase

1.2: Necessity of staircase

1)Protect people from injury and facilitate access during movement from one level to another in a building.

2)Used for the purpose of safe ascent or descent.

3)Also used as a means of escape in case of fire.

1.3: Technical terminology

            Elements of the staircase are as follows:-

staircase

1)Tread

         The horizontal member of a stair, on which the foot is placed while ascending or descending. It is the horizontal distance between two successive risers. It is also known as the “Going”.

2)Riser

It is the vertical member of a stair that supports tread. The vertical distance between two consecutive treads is called “rise”.

3)Step

          Riser and tread together are called step.

4)Staircase

         The volume (enclosure) where the stair is accommodated is the staircase.

5)Stairway/stairwell

         It is the space where the stair is housed.

6)Landing

          Platform left between two flights for circulation and rest is landing.

7)Flight

        Series of steps between landings is flight.

8)Winder

          The trapezoidal tread is called winder.

9)Nosing

        The exposed edge of the tread, projected outward is nosing.

10)Strings/Stringers

          The members receiving ends of steps are stringers.

11)Soffit

       The underside of the stair is soffit.

12)Headroom

           Minimum clear distance between the tread and the overhead structure.

13)Handrail

Protecting member usually parallel to the string, for support while ascending or descending.

14)Baluster

          The vertical infill member between the string and the handrail. A row of balusters surmounted with handrail is known as the “Balustrade”.

15)Pitch Line

      An imaginary line connecting the nosing of all tread in one flight. Pitch or slope is the angle made by the line with the horizontal.

16)Newel

         Post forming the junction of flights with a landing or carrying the lower end of strings.

1.3: Types of Staircase

        Stairs can be classified under two headings:-

1)Classification based on materials

2)Classification based on shapes.

1)Classification based on materials 

       Based on the materials of construction stairs are as follows:-

a)Timber stair

b)Stone stair

c)Concrete Stair

d)Metallic Stair

e)Masonry stair

              The stairs may be built with concrete masonry, wood or with cast iron.  Wooden stairs are at high risk of fire. However, they are used in unimportant buildings to access small areas on the upper floors. Cast iron or steel stairs in the spiral forms were used commonly to reduce the area of the staircase. In many residential buildings, masonry stairs are also used. Reinforced concrete stairs are commonly used in all types of buildings.

2) Classification based on shapes

Based on the shapes stairs are classified as:-

a)Straight stairs

b)Well or open-newel stairs

c)Spiral stairs

d)Dog legged stairs

e)Geometrical stairs

f)Turning stairs

g)Helical etc

1.4: Design of the staircase

-Design procedure

            When the level difference between two floors (ceiling height plus the thickness of the floor slab are given:-

1) Assume the types of building and stair and accordingly the size of the riser(R).

2) Find the number of risers by NR=(level difference/size of the riser).

3) Find the number of treads by NT =(NR-1).

4) Assume the size of tread (T).

5) Assume the width of the stair.

6) Consider the size of landing (L)equal to the width of the stair.

7) Assume the entry space (E), generally equal to landing).

8) Find the total length of stair =(NT*T)+L+E.

9) Adjust the size of riser and tread if required.

Salient Points to be considered in Locating Stairs 

The following points should be considered in locating stairs in a building:-

(A) They must be located near the main entrance to the building.

(B) There should be easy access from all rooms without disturbing the privacy of the rooms.

(C) There should be a spacious approach.

(D) Good light and ventilation should be available.