How many liters are in the bath? How to count? Examples of calculations with formulas

In recent years, installation in bathrooms, especially small ones, of compact shower cabins is gaining popularity. However, most people are in no hurry to give up the pleasure of soaking in a bathtub filled with warm water with fragrant foam. Children are especially happy about this opportunity. So how many liters of water are consumed when taking one such water treatment? We delve into.

Standard bath volume 1.7 m and 1.5 m in liters

In plumbing stores, where most ordinary people shop, the most common are bathtubs of standard sizes in the form of an elongated bowl with a slight bevel under the back and sides at the top. The outer edge of the sides forms a rectangle (for ease of installation in a corner or along a wall). It is these rather bulky sanitary facilities that are present in 90% (no less) of the apartments of our compatriots.

According to metrologists, the volume of such a bathtub in a cast-iron design with a length of 1.5 m and a depth of 0.4 m is from 140 to 170 l, depending on its width. If the length is 1.7 m, it can fit from 180 to 245 liters of water.

In the old housing stock there are sometimes "sitting" baths of 1-1.2 m. Their volume is 95-100 liters.

Attention! Length and width in this case mean the distance between two outer opposite edges.

How to measure the volume of your bath?

Capacity is usually stated in the documentation that came with the product when purchased.

By the way! In the passport, occupancy is usually indicated to the overflow line.

If the document is lost (for example, plumbing 10 years or more), and you want to independently determine the volume of your bath, there are three options for how to do this.

If there are water meters, use the easiest way.. Before the next water procedure, record their exact readings on paper (including all black and red numbers), then fill the bath. Then write off the new data and calculate the difference. This method is good because it does not depend on the shape of the bath and is suitable for any of its models, and the calculation itself is simple and does not take much time - exactly as much as the water is collected, plus 2-3 minutes to solve a simple example.

By the way. In the absence of meters, the payment is made according to the standards, and they do not depend on the actual value of the resource consumption, so you can pour water calmly.

If you want to train your brain, try the second method. It will require the following actions:

• First of all, figure out what geometric shape resembles the inner surface of your bath (school knowledge of stereometry for grades 10-11 is useful);
• remember the volume formulas of the box, ball, ellipsoid, cylinder, truncated pyramid, etc .;
• make the necessary measurements and make the calculations.

With this method of calculation, errors are inevitable, since only a few bowls can “boast” of an ideal geometric shape.

If you want to get the most reliable information about the volume of a bath, stock up on a canister (a 5-liter bottle will come off) and patience. Of course, spend a lot of physical strength, but the soul will be calm.

Calculation example

Consider simple option. Denote the initial readings of cold and hot water meters - a and b, and the final a1 and b1. To calculate how many liters of water was used, use the template:

((a1 + b1) - (a + b))

An experiment in my bathroom:

a = 337960, b = 77750, a1 = 338100, b1 = 77840;

V = ((338100 + 77840) - (337960 + 77750)) = 230 l.

Difficult option. I have a standard cast-iron bathtub 170 × 70 × 40. Its internal shape can be called conditionally parallelepiped (more simply, rectangular).

I measure the required values ​​(at the level of the overflow line, in cm):

• L (length) = 150;
• B (width) = 55;
• H (height) = 30.

I substitute my numbers in the formula:

V = L × B × H = 150 × 55 × 30 = 247.5 L.

It turned out more than in previous calculations. It’s understandable the narrowing and rounding of the surface downward, on the sides and bevel of one of the walls was not taken into account. Hence the extra liters.

We determine the sizes of various forms and types of bathtubs

The volume of each bath is determined primarily by its internal form. There are many different models on the plumbing market. With a rectangular bath sorted out, consider other options.

Rectangular with beveled sides

The volume of such a bath is calculated using the formula for a truncated pyramid (only in our case it is inverted):

V = 1 / 3H × ((L1 × B1 + L2 × B2 + √¯ (L1 × B1 × L2 × B2)),

where H is the height, L1 and B1 are the length and width of the bottom, L2 and B2 are the length and width of the water surface, √‾ is the square root.

Round

We calculate the volume of half the ball:

V = (4/3 × π × R3): 2,

where R is half the diameter of the inner surface at the water level. The calculation will be almost ideal if this value coincides with the depth.

Oval

If the bath is in the form of half an ellipsoid (a ball flattened laterally and elongated in length), we use the expression:

V = (4/3 × π × ½L × ½B × H): 2

π = 3.14, ½L, ½B and H, respectively, half length, half width and height. If the last two indicators are equal, the result will be more plausible.

If the bottom is not sloping, but flat, we calculate the volume of the cylinder with an oval base:

V = π × ½L × ½B × H,

using the same measurements as in the previous case.

Corner

We assume that its shape is similar to a quarter of a regular or elliptical cylinder.

For the symmetric option:

V = (π × R2 × H): 4,

where R is the length of one of the inner walls coming from the corner of the bathroom (they are the same), and H is the depth.

For an asymmetric model:

V = (π × L × B × H): 4,

where L is the length of the larger wall, B is the smaller wall, H is the depth.

Custom bathtubs

These include specimens with bevels on one side or bizarre bends. The greatest difficulty arises with the measurement of just such bathtubs. Their forms are sometimes amenable to "disintegration" (conditionally, of course) into two or more components of the correct geometric shapes, then you will have to create a complex combination of various formulas. Puzzle lovers can try (nothing is impossible for a person with intelligence). However, I recommend returning to the first measurement method using meter readings.

Baby bath

As a rule, it resembles a standard rectangular or oval. You can use the formulas above, but it is much easier to establish the truth empirically. The volume of this capacity does not exceed, as a rule, 35 l. It is recommended to bathe newborns in boiled water, and at first it is not necessary to pour a bath to the brim. So prepare in advance 2-3 containers of 5 liters, boil the rest immediately before bathing and determine what volume is needed for bathing your baby.

How much water is needed to take a bath?

For one water procedure, 100-150 liters of water is enough if the bath is not more than 170 cm in length. You can pour it to the overflow hole, but you need to remember the law of Archimedes. We rephrase it this way: the larger the body placed in the typed bath, the more water it will displace from there. Love to save - pour as much as necessary for a complete immersion, nothing more.

In Russia, unlike many European countries, the payment per cubic meter of water according to the meters is quite affordable. Therefore, many people think less about saving than about personal comfort, which makes it possible to relax in your favorite bath after a busy day.