www.bulit-glass.bg> FAQ

FAQ

1. What is the price of your products?
The price is formed according to the following factors:
  • Glass type
  • Glass thickness
  • Unit quantity, square area and linear area
  • Glass pane cutting optimization (the amount of wastage)
  • Manual labor costs
  • Additional processing costs
Each order is strictly individual and the cost can be determined only after analyzing the above parameters. We are able to give our customers the exact price in written only after an official inquiry on their side, which also must be in a written form. Our standard offers are only an approximation. Any serial production inquiries undergo an individual price negotiation with the client in order to achieve best conditions for both sides.
2. How does one submit an inquiry?

For the correct processing of your inquiries, it is necessary to send a written inquiry by e-mail to office@bulit-glass.bg or via filling out the contact form.

Please note that telephone or on-site pricing cannot be provided.

For the formation of the price, the following details must be provided:

  1. Type of product: tempered glass, laminated glass or double-glazed windows.
  2. Type of glasses for the relevant products and:
    1. for double-glazed units: structure of the double-glazed units, which includes types of constituent glasses, thicknesses and type of spacer frames, type of secondary sealant (polysulphide or silicone) and presence of argon in the chamber(s).
    2. for laminated glass: number and type of intermediate layers (EVA) and whether the glass will be heat treated – quenched or heat hardened.
  3. Indicative or possibly final dimensions and number of the relevant products.
  4. A sketch with clearly written dimensions/distances in case it is necessary to drill holes or make cutouts in the glasses. It is preferable to provide them in vector format (PDF, DWG, DXF), which will speed up the information processing process, as well as avoid additional costs for the preparation of technical drawings on our part.
  5. Graphic file or sketch in case of frosted glass or ceramic printed glass.
3. What is the warrany of your products?

“Bull-It Glass” Ltd. guarantees the quality of the materials used and the sealing in the production of glass units with a 5-year replacement guarantee, in accordance with the complaint conditions and “ Instructions for design, manufacture, safety, durability, storage, installation and operation of double-glazed windows ”. and 5 years anti-delamination of laminated glass, consistent with "Characteristics, application, instructions for manufacturing, safety, transportation, storage, installation and operation of laminated glass."

4. What is the claim policy?

IMPORTANT:
The warranty conditions of "Bul-It Glass" Ltd. are valid only upon presentation of a payment document. Complaint claims can only be made by the individual or legal entity to whom the payment document was issued. Upon approval of a complaint, “Bull-It Glass” Ltd. undertakes to repair or remanufacture the defective products and does not bear costs related to transport, installation and other indirect costs, unless there is a pre-signed contract that regulates different from the above-mentioned conditions.

For double glazing:

Defects covered under warranty:

  • Depressurization of the glazing unit.
  • Deviations from manufacturing accuracy and visual defects greater than those permitted in standard EN-1279.
  • Presence of moisture or contamination in the inner volume of the glass unit.
  • In case of structural glazing, detachment of the glazing unit from the facade structure.
  • Breakage during transport, before signing the delivery protocol/goods receipt.

Defects not serviceable under warranty:

  • Glass breakage during manipulations related to installation. During operation or for reasons such as natural disasters, fire, etc. malicious actions leading to damage to the glass units.
  • Depressurization of a double-glazed unit, due to broken glass, improper installation or insertion of materials incompatible with the materials inserted into the double-glazed unit.
  • Scratch of glass on the external surfaces or breakage, after written handover protocol/goods receipt.
  • Damage to the exterior coating due to scratching during maintenance or cleaning with inappropriate materials and chemicals. For more information, see "Instructions for the design, manufacture, safety, durability, storage, installation and operation of double-glazed windows.".

For laminated glass:

Defects covered under warranty:

Defects not covered under warranty:

For toughened/temperature-strengthened glass, as a stand-alone product or as an element embedded in double-glazed or laminated glass:

Only deviations from manufacturing accuracy and visual defects greater than those permitted in standard EN-12150 and EN-1863 are covered by the warranty.

 

Contact person:
Tsvetan Dimitrov
Deputy Manager at "Bull-It Glass" Ltd.
Company phone: 00359 52 762 152

 

5. What is Low-E (low emittance) glass?
Low-emittance (Low-E) coating are microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface primarily to reduce the U-factor by suppressing radiative heat flow. The principal mechanism of heat transfer in multilayer glazing is thermal radiation from a warm pane of glass to a cooler pane. Coating a glass surface with a low-emittance material and facing that coating into the gap between the glass layers blocks a significant amount of this radiant heat transfer, thus lowering the total heat flow through the window. Low-E coatings are transparent to visible light. Different types of Low-E coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain.
6. What is the difference between Low-E glass with soft and hard coating?
There are two types of Low-E glass: hard coating and soft coating. As you might imagine, they have different properties. In fact, they actually look different.Hard coated Low-E glass is manufactured by pouring a thin layer of molten tin onto a sheet of glass while the glass is still slightly molten. The tin actually becomes "welded" to the glass. This process makes it difficult or "hard" to scratch or remove the tin. Often this glass has a blueish tint to it. Soft coated Low-E glass, on the other hand, involves the application of silver, zinc or tin to glass in a vacuum. The glass enters a vacuum chamber filled with an inert gas which is electrically charged. The electricity combined with the vacuum allows molecules of metal to sputter onto the glass. The coating is fairly delicate or "soft." Furthermore, if silver is used (and it often is) this coating can oxidize if exposed to normal air. For this reason, soft coated Low-E glass must be used in an insulated glass assembly. Sealing the soft coating in between two pieces of glass protects the soft coating from outside air and sources of abrasion. Also, the space between the two pieces of glass is often filled with argon gas. The argon gas inhibits oxidation of the metallic coating. It also acts as an additional insulator. The two types of Low-E glass have different performance characteristics. The soft coat process has the ability to reflect more heat back to the source. It typically has a higher R value. R values are a measure of resistance to heat loss. The higher the R value of a material, the better its insulating qualities.
7. What is the K-Glass (Ka Glass)?
The K-Glass is very popular on the Bulgarian market. It is in essense a Low-E glass with hard coating by a company named Pilkington. It is mistakenly compared to the Low-E glass with soft coating and offers worse qualities in general.
8. What is tempered (toughened) glass and how does one toughen the glass?
Tempered glass is one of two kinds of safety glass regularly used in applications in which standard glass could pose a potential danger. Tempered glass is four to five times stronger than standard glass and does not break into sharp shards when it fails. Tempered glass is manufactured through a process of extreme heating and rapid cooling, making it harder than normal glass.
9. How much does a tempered glass weigh?
The process of tempering the glass does not affect its weight. It is calculated by the formula M = 2,5 kg. * the glass thickness in milimeters. * m2 (square meters).E.g. 1 m2 float glass with thickness of 4mm. weighs: M = 2,5 * 4 * 1 = 10kg.(10 kilos ~ 22 pounds)
10. Why can the glass no longer be processed after it has been tempered?
The tension created inside the glass by the tempering process would lead to immediate breakage in case of any processing attempt. All processing must happen beforehand. Only suraface processing (e.g. making the glass matted) is possible after tempering the glass.
11. Why are there optical deviations when looking at a tempered glass under a certain angle?
The process of tempering the glass creates tension areas in it. These sometimes cause a dobule optical diffraction which under certain conditions become visible. This phenomenon is physically acceptable and normal for the tempered glass and could not be a subject of claim.
12. What is the coefficient of heat transmission (U-value)?
U-value (Europe) Heat-transfer coefficient The heat-transfer coefficient (or U-value) is the amount of heat in watts transmitted per hour through 1 m2 of wall (glass) with a difference of 1 Kelvin Degrees between the inside and the outside (W/m2.oK).
13. Why does the IGU sometimes inflate or deflate?

The insulating glass unit (IGU) is a solid closed unit in respect to the air and responds to the air conditions. Any change of air temperature or air pressure reflects on the IGU"s volume as well. This is a normal reaction of the IGU and cannot be avoided or a subject of claim. However, it can be minimized if the IGUs are put together vertically and manufactured on an altitude close the one of the place where they will be installed.

For example:

  • Inflation - if the IGU was manufactured in March under 18oC, in August under 30oC it will look slightly inflated. If the IGU was manufactured in Varna and installed some place in the mountains where the air pressure is lower it will again look slightly inflated.
  • Deflation - deflation works the opposite way. If the IGU was manufactured in June, in January under negative temperature, it will look slightly deflated. If it was manufactured in Sofia and installed in Varna, because of the air pressure difference, it will look slightly deflated.
14. Why does the IGU sometimes condensate?

Moisture condensation – The temperature at which the relative humidity of the air is 100% is called the dew point. Condensation is expressed in the appearance of drops of moisture on the surface in the following cases:

  • In the very structure of the glazing between the panes: in this case the dew point is below – 60C. If, in another case, condensation is observed inside the glass unit, then its manufacturing is not correct. This defect is unacceptable.
  • Condensation can occur on the inner surface of the double-glazed unit from the room when warm and/or moist air comes into contact with the cold glass surface. To avoid this effect, it is necessary to improve the air ventilation and use a glass unit with a lower coefficient of heat transfer. When using low-emissivity glass with a soft coating, the issue of condensation on the inner surface is almost solved.
  • On the outer surface of the glazing outside the building itself: under certain circumstances – intense cooling of the outer surface and humid air, especially early in the morning, sweating may appear, which quickly disappears. Condensation of moisture on the surface of the glass unit from the room or the environment is physically determined and cannot be the subject of a complaint.
15. What is the greenhouse effect?
Due to the high light and heat transmission factor of the regular transparent glass, sun light goes into the room easily and warms up the floor, walls, furniture, etc. On its way back the heat waves are reflected by the silver coating of the low-e glass and thus they remain inside. During the winter this occurance contributes to lower heating costs. In the summer however, the energy generated by the greenhouse effect brings discomfort which can be avoided with appropriate solar protection.
16. Is there an optimal glazing using insulating glass units?

Yes, but it is individual according to the situation and the purpose of the building. In order to achieve optimal characteristics of the glass units, as well as optimal costs for them, it is necessary to select the right structures. Please note that “optimal” does not mean lowest costs, but rather costs of “correct” a structure with which maximum comfort and efficiency can be achieved without making unnecessary costs for glasses offering functionality that we may not need.

Some of the parameters that may be considered are:

  • Orientation of the facades and, accordingly, how much they are exposed to the sun – in our hemisphere, there is no need to install sun protection glasses on northern facades, as there is no direct sunlight.
     
  • In shady areas, such as wooded areas, regardless of the orientation of the facades, sun protection glass can be completely avoided, since even in summer there is no strong direct sunlight.
     
  • Although laminated glass glazing provides the best sound insulation, in quieter areas such as small streets for example, optimal (although not maximum) sound insulation can be achieved by placing monolithic glasses of different thicknesses (6mm + 4mm for example) to avoid resonance.
     
  • Single- or double-glazing: when maximum thermal insulation (low U-value) is sought, even with existing window frames with single-glazed windows, it may be a better solution to replace them with double-glazed windows. The reason is that even the most common double-glazed unit with one soft-coated low-e glass and two clear glasses, in combination with argon-filled chambers, can provide a U-value of 0.9W/(m².K) . This is currently the best value that can be achieved with single-chamber glazing, and for it some of the most expensive glass on the market must be selected. In such cases, one can think about the costs of joinery and assess which is the more reasonable option. A relatively affordable double-glazed structure that achieves a U-value of 0.5 W/(m².K) is a combination of solar control glass on the outside, clear medium glass and low e glass with a soft coating on the inside, again requiring the chambers to be filled with argon or other inert gas.
     
  • Sun protection, light transmission and cooling costs: inevitably, good solar protection is a compromise and balance between how much light is transmitted into the room and how much of it is reflected by the glass coating or absorbed by the glass mass. The darker, the cooler. The solar factor (SF) of the most ordinary double-glazed unit with two clear glasses is 80%, and the light transmission is 83%. The result of this is that in the summer the glass heats up to over 50-60 °C and all this temperature is transmitted into the room. This has an extremely negative impact on cooling costs. Sun protection glasses have been available on the market for this purpose for many years. “Standard” (most affordable in terms of price) sun protection glasses reduce the solar factor to 39%, and the light transmission to 61%. Visually, the human eye will not perceive much difference in terms of light, but reducing the solar factor by half significantly reduces cooling costs. Despite everything, this glazing will still feel relatively warm to the touch. For a noticeable cool feeling, it is necessary to use glasses to achieve a solar factor below 28-30%. These are special glasses with two or three silver coatings. When using such glasses, light transmission above 50% can rarely be achieved, which can already lead to discomfort in rooms with fewer windows. Please note that in the summer with strong sunlight, the problem of low light transmittance cannot be felt. This is felt mostly during the gloomy autumn-winter days, especially when it rains. In some cases, external blinds or other blackout in combination with standard solar glass is the best combination for a bright and warm room in winter, spring and autumn, and cool (albeit dark) during the hottest hours of summer days.< /li>
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