In the US, the cemeteries usually requests the use of a vault in order to prevent the caving in of the grave (either by the deterioration of the casket or by the use of heavy machinery for maintaining the cemetery). Oftentimes the relatives buy a vault also for reasons of peace of mind because a hermetically sealt vault protects the casket (at least for some decades) from the entering of ground water or insects. But there is no law that requires the use of a vault.
In the US, there is no law requiring the casket to be placed in a vault. But many cemeteries make such request because they want to avoid the caving in of graves as a result of either the deterioration of the casket or the use of heavy machinery for maintaing the cemetery.
Possible, but unlikely. In most places, a casket or coffin is placed in a metal or concrete vault which is placed in the grave before the casket.
The main benefit is for the cemetery: a vault prevents the grave from caving in as a result of a breakdown of the casket and / or the use of heavy cemetery maintenance machinery. In addition to that, a - hermetically sealing - vault may provide the relatives with the peace of mind that at least for some decades no groundwater and no insects can enter the casket.
Define burial vault. If you are refering to the out container that a casket is placed into I refer you to ---- http://www.cemeteries-of-tx.com/LAWS.htm
In the US, a burial vault is not required by law. Oftentimes it is required by cemetery regulations because a vault prevents the grave to cave in as a result of a deterioration of the casket and / or the use of heavy cemetery maintenance machinery.
The flag should be placed smoothly and gently around the casket; the stars should be at the bottom of the casket and the d trips are at the top,
A (sealed / air and watertight) burial vault or an (unsealed /non-protective) grave box.
Burial vaults protect the casket, while casket liners protect the body in the casket. Casket liners are either used for long distance shipments (especially overseas) or for protective purposes in wooden luxury caskets. The former ones are usually made of zinc (sometimes possessing a small glass lid), the latter ones are usually made of copper or bronze and have oftentimes a full length oval plate glass lid.
To properly place a flag on a casket, the flag should be draped over the casket with the union (the blue field with stars) positioned at the head and over the left shoulder of the deceased. The flag should be spread evenly and not touch the ground. It is important to ensure that the flag is not used as a cover or a covering for any other items, and it should remain in a respectful position throughout the service. If the casket is to be transported, the flag should be removed and folded according to proper flag etiquette.
Check state laws, most will allow it, however some cemeteries have rules as to the type of casket they will take, or may require an additional concrete vault. Babies, especially stillborn ones, usually have more lienient rules.
a pall (or casket pall / funeral pall)
No, not at all. At least there is no US law requiring a vault. On the other hand, most American cemeteries request vaults in order to prevent the graves from caving in - either as a result of the deterioration of the casket or of the use of heavy cemetery maintenance machinery.