Used to protect premises from X-rays, a widely used modern alternative to expensive lead screens. Recommended for finishing X-ray rooms, physical laboratories and industrial facilities with hazardous radiation values. The composition meets the requirements of the provisions of GOST 4682-84, the amount of barium sulfate (BaSO4) must be at least 85%. During work, you need to apply respiratory protection measures - barium sulfate powder has a negative effect on health. After finishing the plaster, it is recommended to additionally cover the top layer with finishing materials to prevent the ingress of barium sulfate dust into the air.
The composition of the material includes cement and plasticizers.
Cabinet finished with barite plaster
During application, the manufacturer's recommendations must be followed exactly both in the thickness of the plaster and in the application technology ... The cost of the complex of protective measures against X-rays using plaster is much lower than finishing of premises with lead plates.
Currently, industrial companies produce several types of barite plaster, differing in composition, price and physical properties.
|Brand name||Chemical composition||Approximate price|
|Barite crumbs, cement and plasticizers||Bag 25 kg - 64-70 rubles.|
SOREL BARIT M150
|Barite crumb, magnesia binder, polymer plastic additives||5 l of hardener + 25 kg of mixture - 1200 rubles.|
|Barite crumbs, cement and plasticizers||Bag 25 kg - 750 rubles.|
|Barite crumbs, cement and plasticizers|| 25 kg bag - 780 rubles.
|Barite chips + magnesium||Bag 25 kg - 900 rubles.|
Barite concrete M200 is used to protect against strong radiation, the maximum thickness of a single-use layer increases to 6 cm, can be used both for plastering walls and ceilings, and for pouring floors and creating interroom partitions on the formwork.
Barite concrete M200
Alternative protective materials must meet the requirements of SanPin 2. 6. 1.
1192-03. The thickness is calculated taking into account the requirements of the design documentation of the X-ray room and the maximum power of the rays in laboratories or industrial premises.
Approximate consumption and the ratio of the protective parameters of barite plaster to the thickness of lead slabs
|Thickness of the lead shield||Approximate consumption per square meter||Thickness of barite plaster|
|1 mm||45-47 kg||10 -11 mm|
|2 mm||84-86 kg||20-21 mm|
|3 mm||148-150 kg||29-30 mm|
|4 mm||205-210 kg||35-37 mm|
The required thickness of barite plaster should be determined by the thickness of the lead plates. Lead parameters are specified in the design documentation and depend on the power of X-ray radiation. Sanitary norms and rules establish requirements for ensuring the safety of personnel and visitors to clinics.
When the design capacity of the equipment changes, appropriate adjustments are made to the degree of protection, all actions must be coordinated with sanitary organizations without fail.
Consumption of barite plaster
Important. The data given in the table on the thickness of barite plaster are approximate and vary depending on the specific type of material and its physical properties.
Shielding performance of plasters must be confirmed by the test report, carried out in accordance with GOST 12. 4.
217-2001. The test data cannot be used when recalculating the protective layer thickness for other materials, each of them is subject to mandatory individual verification. For example, consider the procedure for preparing some types of barite plasters.
The mixture consists of two components: dry powder of barite concrete with polymer and hardener, powder weight 24 kg, hardener volume 6 l. Always use a respirator when preparing.
The components are thoroughly mixed in a concrete or mortar mixer until a homogeneous composition is obtained. Water is added to obtain the required consistency depending on the use. For plastering, a more liquid mixture is needed, for concreting a floor or pouring walls, a more viscous one is needed.
Important. The finished mixture should be used within 45 minutes, then irreversible polymerization processes begin.
Decide on the quantity, taking into account labor productivity and material costs.
Ready mix can be used for:
Physical indicators of strength make it possible to use any materials for the finishing flooring;
The protective plaster or grout is very thick. To improve strength and reliability, load-bearing walls must be reinforced. How is it done?
Buy a metal mesh reinforcement. The diameter of the wire and the size of the cells are selected taking into account the thickness of the protective layer of barite mixtures.
Metallic reinforcing mesh
Step 2. In a staggered pattern with a step of about 50 cm, fasten in the carrier wall dowels. In the wall, the length of the dowel is at least three centimeters, the height of the cap should be half the thickness of the plaster or fill.
Taking these parameters into account, select the length and diameter of the dowels.
We fix the dowels in the wall
Step 3. Tie the metal reinforcing stack to the dowels with copper or aluminum wire ...
Check its position, do not allow swelling.
We attach a reinforcing mesh to the dowels
If everything is prepared, you can start plastering or pouring. We will describe below how this is done.
It is impractical to prepare barite plaster from the components on your own. Due to the impossibility of precisely controlling the percentage of elements, the shielding values are unknown.
Each individually manufactured batch must be sent for inspection to state laboratories to obtain a certificate of conformity. It is recommended to purchase ready-made formulations indicating the exact content of fillers and shielding characteristics.
Barite plasters can be produced with cement or magnesia fillers. Materials have significant differences in physical and performance characteristics.
|Performance||Magnesia Filled||Cement Filled|
|Approximate material consumption per 1 m2 of area with 10 mm plaster thickness||14-20 kg||21-24 kg|
|Approximate unproductive losses||None||Up to 20%|
|Maximum possible thickness||Up to 40 mm||Up to 60 mm|
|Features of the application technology||Each layer requires at least 7 days to dry||Drying time is about 24 hours|
|Resistance to cracking||Medium||High|
| Layer thickness at one time ||3-30 mm||7-12 mm|
The material is much more expensive than ordinary plaster based on anion of a cement-sand mixture.
This feature puts forward special requirements for surface preparation.
Step 1. Examine the wall surfaces. If there are old coatings, then they should be removed. Large cracks and irregularities must be repaired.
The smoother the layer of barite plaster, the less expensive material is consumed.
Preparing and cleaning the wall before plastering
Step 2. Wait until the wall is completely dry. Remove its dimensions, calculate the approximate amount of plaster depending on the thickness of the layer.
Measure the room
During the calculations, it is necessary to take into account the design documentation of the room with X-ray equipment and the requirements of sanitary norms and rules for screening.
Step 3. Be sure to wet the wall surface with a primer. Cover twice in perpendicular directions. The fact is that the minimum thickness of the plaster is approximately 20 mm, the weight is large, all measures must be taken to increase adhesion.
Apply the primer to the wall
Step 4. Set up the beacons. It is advisable not to use metal ones, but to make them from barite plaster, such requirements are in the regulatory enactments. How to make plaster beacons?
Clean the wall from dust, remove all construction debris from the flooring.
Draw vertical lines for the level on the wall.
The distance between them should be 25-30 cm less than the length of the rule.
Prepare a small portion of barite plaster, mix thoroughly until all lumps are removed.
Spray the vertical line with a spray bottle and pour a barite solution over it. Throw it from bottom to top in a line, the width of the stripes is about 5-8 cm
the thickness is not less than 2 cm.
Installation of beacons
Use a tape measure to measure the thickness of the sketched strip at the top, bottom and several places in the middle.
Take a long level, place it with its edge in the sketched strip and with light cyclic indentation achieve a vertical position at a distance of 2 cm from the wall surface. You should have a smooth groove in the grout.
With a trowel, very carefully remove the protruding bumps of the mortar. If necessary, correct the surface of the beacon, it should be as flat and vertical as possible. Using this algorithm, make two extreme beacons.
Give them time to grasp.
Pull the horizontal ropes between the extreme top and bottom and throw the remaining beacons over them.
Leave the beacons for at least a day to solidify reliably. The surface must be solid, otherwise, during the leveling of the mortar as a rule, it will fall through, which will greatly complicate the plastering process.
How to install beacons
After the beacons have become solid, start plastering the wall.Throw the mortar from the bottom up between two adjacent beacons. Thickness within a centimeter. The fact is that you have to plaster twice, one layer cannot have a thickness of two centimeters, wide cracks will appear during drying. Experienced craftsmen immediately throw the mass to a height of about half a meter, you can try with smaller volumes.
Plaster the wall
Step 6. While the mass is not frozen, level its surface using the rule. Pull the tool from bottom to top and constantly move it from left to right. Throw the solution accumulated on the rule back into the container and mix. The surface of the first layer of plaster should not be even, the more depressions and bumps there are, the better the second layer will hold.
Anything thicker than two centimeters, remove the rule.
The rule is to align the wall
Step 7. After the first bottom section of the wall is sketched and aligned, throw the barite plaster above between the same beacons. And so on up to the ceiling.
Apply barite plaster
Finished the section between the first beacons - go to the next. We assure you that there will already be practical experience, it will become much easier to work. The mass will not fall off the wall, spray will stop in all directions. You will know how much mass to take with a trowel, how hard to throw it and in what directions to move your hand. Experience is a great power.
The next layer of plaster can be applied on the second or third day. Specific terms depend on air humidity, temperature and ventilation in the room.
The surface of the second layer of barite plaster must lie exactly in the same plane as the beacons. If there are depressions, refill them with mortar. An important point is surface grouting, it must be done skillfully.
Only start grouting when the mass is similar in consistency to soft butter. If you start earlier, the surface will only deteriorate, you will make indentations. If later, it is difficult to level, and a thin layer of mortar may flake off. Slight moistening of the surface is allowed during grouting. Use a special brush, soak it in a bucket of water and spray the surface to be rubbed.
Grouting the plaster
Make only circular movements with the tool. Low mass - add a little to the grooves. During work, the edges of the grout should always lie on a flat surface, grind the mass with the middle. No experience - first work on a small area, the skill appears - increase the areas being rubbed at the same time
Method of troweling plaster
At the beginning, the leveling force of pressing should be minimal, the grout can be pressed a little harder only after large irregularities corrected, but everything should be done carefully, not in a hurry. Remember that ruining the surface is much easier than re-leveling it later.
Barite plaster is unsafe for health, microparticles of a chemical element can enter the lungs and cause various diseases. To prevent such situations, the plaster must be protected after complete drying. The easiest and cheapest way is to paint the walls with oil paints. But you can also paste over with wallpaper or make sheathing with panels of various materials. The specific finishing method should take into account the peculiarities of the operation of the premises.
If the thickness of the plaster layer exceeds 2 cm, then it is faster and more reliable to fill the wall under the formwork. We have already mentioned that in this case it is necessary to fix the metal reinforcing mesh.
Important. The length of the dowels protruding above the wall surface used to fix the mesh should be equal to the thickness of the poured layer. How to make formwork? Consider two manufacturing options: from edged boards and from special moisture-resistant plywood.
The thickness of the fill is small, you can use edged boards ≈ 20 mm.
Step 1. Measure the wall. If the length is more than three meters, then it is better to make two shields from boards - the risks of deflection are minimized. But a specific decision is made on site, taking into account the size of the protected wall.
The length of the boards is about 1.5 meters, the height is not more than one meter.
Formwork on the wall with reinforced mesh
Step 2. Nail boards to wooden slats 30 * 50 mm, while fixing, press them together as tightly as possible. The distance between vertical slats is no more than a meter.
Step 3 . Turn the board right side up, check the position of the boards. If you find any differences in height, remove them.
Step 4. Lean the formwork against the wall, it should rest against the caps of the screws.
Check the verticality level, if necessary, correct the position.
Step 5. Secure the formwork with corner supports.
Plank formwork on the wall
Pour barite plaster from above, level it constantly. If you have an electric vibrator, great, use it to remove air from the mass.
If not, constantly tap the formwork with a hammer until the mass stops settling.
Step 6. When the mass hardens, remove the formwork and install it higher on the wall in the same way. It will take at least a week to solidify, do not rush to plan the boards. If the mass has not gained strength, then there are high risks of deep cracks or delamination.
There is always a gap between the wall and the ceiling, it will have to be plastered several times with a trowel.
After finishing work, remove any irregularities. Given their size, they can be cut or wiped.The final leveling of the wall plane depends on the finish. For painting or wallpapering, the wall should be of the highest quality, for wall upholstery with various panels, alignment can be omitted.
Ready X-ray room
If there are waterproof plywood panels for formwork - great, the work will go faster, the wall plane will be of better quality.
Keep in mind that a concrete screed will have to be made on top of the barite layer, the strength of the material is insufficient for heavy X-ray installations.
Before starting work, you need to level the concrete base, as a rule, it is a reinforced concrete floor slab. The solution is applied along the lighthouses, the alignment is done by a rule or by a long, even wooden lath at least 5 cm wide. The only condition is to wear a respirator while preparing the solution.
Concrete floor screed
If there is no experience - do not take for such work.
Step 1. Clean the concrete slab from dust and dirt. Found large cracks and irregularities - close them up. The fact is that the thickness of the barite plaster must be the same over the entire area, and this cannot be achieved on an uneven base.
Step 2. Moisten the surface with primer twice in transverse directions.
Priming the ceiling
Practical advice. The coefficient of adhesion of barite plaster to the concrete slab will increase significantly if cement laitance is applied to the ceiling before plastering. To do this, dissolve water with cement in a small container to the consistency of liquid sour cream.
The solution should be thrown onto the ceiling with a ladle; after hardening, small "icicles" will hang from the ceiling. They significantly increase the area of contact of the barite solution with the base. The method is very old, but fails in all cases.
Step 3. Install beacons on the ceiling.
Not obtained from the mass - use thin metal slats, fix them with dowels.
Installation of beacons on the ceiling
Further work is no different from plastering walls, only plastering, of course, is much more difficult. Protect your eyes from the barite mixture, use safety glasses.
Before plastering with barite plaster, all wiring and utilities must have already been laid. It is strictly forbidden to gouge the plaster - there are places with insufficient X-ray shielding.
Never dry the plaster with fans, let alone heat guns. Accelerated drying will not allow the cement to gain strength, as a result, the plaster begins to crumble. And this is extremely dangerous in the case of using barite plaster.
Cracking due to improper drying
Very dry brick walls must be pre-wetted. Such a wall quickly absorbs water, and the adhesion coefficient drops sharply.
If the temperature in the room is higher than + 22-25 ° С, then at the end of the work the wall should be wetted, it is better to do this at night.
Before plastering, it is recommended to check the mortar, if it does not adhere well to the wall, then add a little cement. The lack of cement is also indicated by the rapid separation of the mass into water and solid fractions.
The main advice - barite plaster refers to a complex of special protective construction works, which are subject to very high quality requirements and technology compliance. Take your time, work carefully and responsibly.
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