A general term referring to any container which is designed for placement in the grave around the casket, including, but not limited to, containers commonly known as burial vaults, grave boxes, and grave liners.
- Both vaults and liners must meet the minimum standard of 4500 PSI
Outer Burial Container
To support the weight of the earth over the grave. Any burial not accompanied by such a container is subject to eventual collaspe due to the weight of the earth crushing down on the unprotected casket.
- The resulting "sunken" grave then presents potential groundskeeping and visitor safety concerns.
Primary Purpose of the Outer Burial Container
While these do not require the use of an outer burial container, most cemeteries, in the interest of minimizing maintenance and liability issues, will require either a burial vault or grave liner be used in conjunction with any interment.
State and Federal Law
Forces that the outer burial container is subject to.
Four Load Types
Comprised of the weight of the soil above the outer burial container, as well as the force exerted by the earth against the outer burial container's sides and bottom. Also encompasses the forces resulting from cyclic freezing and thawing of the earth.
- Actual weight value varies depending on soil composition and water content
- Average weight of 18 inch thick covering of earth over an outer burial container is ~4,000lbs (2 tons)
Typically of short duration, can be quite heavy, as in the case when soil from a grave under excavation is placed on top of an existing grave.
- Normally removed within a few days, at most
One that varies in its intensity and is usually temporal in nature, such as the weight of a dump truck that might drive over the grave, or the force exerted by a backhoe parked above an existing grave while it excavates another grave nearby.
- Increased over the last few decades (more machinery used today).
Encountered by the outer burial container when a sudden and powerful application of force is introduced to the gravesite, as occurs when a large amount of fill-dirt is dumped onto the outer burial container as the grave is filled, when a mechanical tamper is utilized in filling the grave, or when a backhoe's bucket is forcefully dropped on a grave.
- Brief but can create a tremendous amount of stress in a concentrated area.
- Can easily cause a nonreinforced burial container to fracture and eventually fail.
An outer enclosure which offers protection from the earth load as well as possessing sealing qualities.
- May be constructed from concrete, metal, fiberglass, or plastic polymers.
An outer enclosure which offers protection from the earth load without protection from the elements.
- Most commonly formed from concrete, but may also be seen made from other materials.
May vary substantially. The standard is 30 inches wide by 86 inches long.
- Most manufacturers make sizes compatible with children's cakets.
Outside Dimensions of Outer Burial Containers
A two-piece affair consisting of a bse and cap (or "cover"). May or may not be internally reinforced with smooth steel bar or rebar, and the interior i typically lined with a material designed to further strengthen the structure and to resist the entrance of water.
- Many offer secondary reinforcement by incorporating welded wire fabric (wire mesh) within the vault's component pieces.
Concrete Burial Vaults
- Polystyrene plastic
- ABS (acrylonitrile butadiene styrene)
- Various wrought metals (stainless steel, copper, or bronze)
Materials Used to Line Concrete Vaults
A very tough and resistant plastic.
ABS (Acrylonitrile Butadiene Styrene)
Placed within the base and cap of the concrete vault. When used, the metal linings are usually present in addition to this initial lining material.
Separate Synthetic Liners
Used by some vault manufacturers a both a lining and an exterior coating. Does little to strengthen the vault structure itself, but does reduce the concrete's permeability.
- Polymer: Similar in appearance to plastic, that has a high molecular weight creating an extremely durable substance.
- Fiberglass: A material consisting of extremely fine filaments of glass embedded in various resins
These are available through some manufacturers as an alternative to the traditional concrete and metal vaults.
Polymer and Fiberglass
As a result, specialized and expensive equipment is necessary to transport the vault from its place of manufacture to the cemetery and install it within the grave.
- Most funeral homes choose to have these installed by a local vault dealer
- In many instances this dealer will provide the cemetery "set-up" or casket lowering device, tent, and chairs.
Concrete Burial Vaults Weigh in Well Over 2,000lbs (1 ton)
Used by nearly every concrete burial vault. A method of closure that utilizes an epoxy compound in conjunction with tongue-in-groove construction at the top edge and the lid of the vault.
- Uses the weight of the vault cover and earth load to its advantage producing contact between the groove:
- Within the vault cover
- The sealing compound or epoxy
- And the tongue
Top Seal Method of Closure
- Decorative: Concrete surface may be swirled, patterned, or coated wtih sand. Painted in a color complementary to the chosen casket. Non functional handles or embellishments such as nameplates, crucifixes, or military emblems.
- Protective: A superficial coating of asphalt
- Both decorative and protective: an external cladding of ABS or bronze.
Concrete Vault Exterior Finishing Treatments
- Available in a variety of metal types and thicknesses. Commonly 12 to 7 gauge.
- Materials: steel (galvanized), stainless steel, and copper.
- Many funeral homes choose to warehouse and service these themselves rather than subcontract
- Consists of a shallow base upon which the casket rests, and a top or "dome" which covers the casket and rests on the perimeter of the base.
- Employ the diving bell (air seal) principal
Metal Burial Vaults
Steel that has been coated with zinc for increased resistance to rust.
A method of closure that utilizes the air pressure created by placing the dome (A) of the vault onto the base (B) of the vault.
Air Seal (Diving Bell)
Gives the unit exceptional load resistance, and its curved interior allows collected condensation to roll down the sides of the vault and back into the earth.
The Arched Dome of the Metal Burial Vault
The top of an air seal burial vault which entraps air as it is put into position; it also supports the weight of the earth above.
- Powder coated
- Natural metal
- These finishes are usually covered with a protective clear coat
- The handles found on these are functional
Metal Burial Vault Finishes
Not as widely used as concrete or metal vaults. Most often constructed using the air seal principal, some feature the top seal method of closure.
- Lightweight and possess an almost unlimited lifespan when placed in soil.
- Can be stacked in a "nesting" arrangement
- Easily stored and transported by funeral homes that choose to service their own vaults.
Fiberglass and Polymer Vaults
- Concrete- typically top seal
- Metal- typically air seal
- Double seal
- Some fiberglass and polymer- gasket in addition to air seal method. Also use the top seal method.
- End Seal (Gasket Seal)
Methods of Closure
A method of closure that utilizes the principle of the air seal in conjunction with an epoxy material at the junction of the done and the base of the vault.
A rubber gasket, held in place on the head section of hte vault is the basis for sealing this type of vault.
- Currently not used, but may be seen on disinterments
- Two component parts: the body and the end
- Body- Consisted of the top, bottom, sides and foot end of the vault
- End- Consisted the head section of the vault that opens to allow te casket to be placed inside.
- Once the casket is inserted into the vault the head end section of the vault is bolted to the body secton with a rubber gasket betwe the two sections to create a seal.
- Always constructed of metal, primarily steel.
End Seal (Gasket Seal)
Sole purpose is to support the weight of the earth covering the grave; it incorporates no provision for inhibiting the entrance of water or soil.
- Most commonly constructed of concrete and, to a much lesser extent, wood.
- Grave box
- Sectional liner
- Dome or bell is another option
Two Varieties of Grave Liners Most Prevalent
An outer enclosure consisting of a body and a one or two piece lid.
- Holes are frequently present in the base so that accumulated water and other fluids may drain away.
- The holes will also allow easy encroachment of ground water should the surrounding water table rise.
A grave liner consisting of six or eight slabs of unfinished concrete placed around the casket in the grave.
Concrete Sectional Liner
This grave liner consists of a dome or bell shaped top that is placed over the casket, it does not have a base, the casket is placed directly on the floor of the grave.
Dome or Bell
Engineered to provide the same protection for the urn as a vault does for a casket.
- Similar to a full sized vault
- Maintain the same strength characteristics as a casket vault
- Made of: solid copper, stainless steel, galvanized steel, and steel.
- Sealed on the air seal principal.
Metal Urn Vaults