The popular term, VIF as noted on construction documents and specifications, can be a very dangerous and misleading nomenclature, if not fully understood and properly interpreted by the General Contractor, or the Construction Manager on the project.
The term, in its most basic interpretation, is that a dimension, so noted on the documents as VIF, is to be physically field verified by construction personnel, once they are on the project. There are a number of reasons that the nomenclature is used on construction documents and within specifications.
1.) The designer, engineer or architect is not interested in physically traveling to the project, and taking the actual dimensions required to accurately indicate the dimensions on the contract documents. The project could be too far away, they do not have the travel expense in their budget, or they do not have the proper personnel to perform the field task.
2.) The ability to determine the accurate dimensions, are impossible to determine at the time of the construction document development, for any number of reasons.
a.) The required dimensions are buried beneath existing construction finishes, or other existing material or equipment that will be required to be removed, prior to the ability to obtain the accurate dimensions required. It is physically impossible to identify the dimensions that will correspond to the final design of the project. It simply cannot be done due to an inaccessible situation.
b.) An existing structure’s exact location, is required to properly identify the accurate dimensioning of the new work. This occurs many times when an addition is being attached to an existing structure and the actual dimensioning of the existing structure is unknown. In many instances the demolition of adjacent structures, is necessary to provide the clear site lines required to identify the dimensions needed to properly construct the new phases of the project.
c.) There are no as-built documents for an existing structure, that will remain as a part of the total finished construction project, and all of the existing dimensions will need to be physically verified in the field.
d.) An accurate utility tie in for a utility such as a storm line, sanitary line or another transmission line, must be 100% accurately identified, prior to the manufacture of the adjacent piece that will tie into the existing utility. This accuracy is impossible at the time of the document development and must be noted as VIF. The existing piping ,ductwork or other mechanical systems that will be tied into, must be actually measured in the field, to accurately identify the needed sizing of the matching components.
3.) The dimensioning of a new structure, or the dimension of a construction element, cannot be determined until the new structure has been detailed by the structural steel contractor, and then engineered into the entire scope of the new construction project. This dimensioning relies on the detailing of an adjacent structure or construction assembly. This occurs many times during a project with multiple additions, that are added to an existing structure, such as an academic, commercial, or industrial complex.
4.) The dimension is changing as the project advances. For example the loading of a foundation, or a specialized type of supporting structure, will be dependent upon the final position of the supporting element. If a foundation is being loaded as the project advances, the final dimension of specialized equipment such as earthquake stabilization equipment, may need to be physically measured in the field or VIF once the entire structure has been properly loaded. If the foundation is settling, as the loading progresses, the final location of that foundation will only be determined after it becomes stable or has reached a static position.
5.) An underground structure, such as a subway tunnel, whose location is not exactly known at the time of the document development is intrinsic to the proper dimensioning of another element. These accurate and precise dimensions, will only be known after the structure has been exposed during the construction process. Once the structure is exposed, the VIF nomenclature will be used to instruct the contractor, that accurate and precise dimensions should be taken, which would then allow the design of the adjacent elements to be performed.
These five situations are only some of the reasons that the nomenclature VIF is used by engineers and architects designing a project. There are several additional reasons and occurrences that will cause the designers to simply place the VIF designation on a dimension. Certainly liability, is one of the most important reasons that the VIF is placed on construction documentation.
By identifying a dimension with the VIF designation, the design team has now transferred the liability for the accuracy of the dimension to the contractor or the construction manager. This is the reason that we have titled this webpage as VIF ( Verify in Field ) Contractors Beware.
What issues could occur and develop, with the placement of the VIF designation on the documents, for the contractor or the construction manager?
1.) The liability for the accuracy of the dimension, or dimensions has now been transferred from the design team to the contractor or construction manager. This liability for accuracy, can become a major concern as the project advances, and the importance of accurately identifying this dimension is realized on the project. Acknowledgement of the importance of certain dimensions and details on a project, in many instances, requires time and experience on the project. The contractor or construction manager must realize that at the beginning of the project, their understanding of the project is much more elementary than the design teams. The design team has been living with the details of the project for many months, if not years. This time advantage has clarified, to the design team, all of the elements that they are unsure of, and they now understand the complexity of. The contractor or construction manager, when bidding the project, only has the documents for a very short period of time. All of the VIF designations on the documents have been established by the design team, based upon their lengthy analysis of the design situation as well as their time on the project. The contractor or construction manager has none of these insights or behind the scenes reasoning for the need to identify the dimension as a VIF dimension. It is extremely important that the contractor or the construction manager understands this.
2.) Once the designation of VIF is included on the documents, the need for one or more field measurements becomes a requirement which must occur prior to the detailing of structural steel, concrete foundations, structural concrete, piping systems, ductwork layout, sprinkler details, etc., the effect of this VIF requirement on the project schedule MUST be considered. It is vitally important that the contractor or construction manager understand, where in the schedule these dimensions will effect. If the final structural detailing cannot be completed, until the VIF dimensions are known, then all of the time to obtain the final approvals will occur after the identification of the VIF dimensions. This time element is so important to the overall scheduling of the project, unfortunately many contractors and construction managers, fail to understand this time element and its importance.
3.) The need to VIF a dimension, must be clearly understood that it is a catalyst for other activities. In many instances, a VIF dimension is not close to the anticipated dimension that the contractor had tried to approximate, at the time of development of the construction schedule and construction pricing. If the VIF dimension is something that was not anticipated, then how can the construction schedule or the actual construction budget be accurate? Although the VIF designation is easily used by the design team, its effect on both the schedule and the budget can be substantial.
4.) It is important that the contractor or the construction manager, transfer all of the liabilities that are generated by the use of the VIF designation on the documents by the design team, onto the subcontractors hired for the project. For example, if the structural steel design is based upon the identification of various VIF dimensions, then the scope of work for the structural steel subcontractor must include all of the delays and liabilities that this VIF designation may have on their work.
5.) The accuracy of the actual VIF activity is vital to the success of the project. Due to this importance, it is in the best interests of the contractor or the construction manager, to insist that a representative of the design team be instrumental in the final establishment of these VIF dimensions. Insist on a field representative be on the project, from the design team when the measurements are being made. In addition, a verification email must be sent to all parties, inclusive of the design team as well as the owner, acknowledging that the dimensions were actually verified, and that a member of the design team witnessed this verification of dimensions. Documentation is vital to the VIF process!
6.) The construction schedule should clearly identify the timing of the VIF procedure in the field. It is important that the design team and the owner clearly understand the scheduling ramifications of the VIF designation. It is imperative that the contractor or construction manager, from the onset of the project clearly identify, on the construction schedule, the time required to perform the VIF dimensions as well as the time that is required, after the VIF dimensions are verified, on the remaining activities that were affected by this VIF activity.
7.) If the VIF dimensions are much different than expected, by either the design team or the contractors on the project, then this must be clearly noted by the contractor or construction manager, and a change order issued to identify any additional costs or time involved, due to this VIF of dimensions. This is very important for the contractor to ensure, that due to the shift in the liability for these VIF dimensions, the timing and the costs of this shift of liability does not negatively affect the contractors contractual relationships or their legal agreements for the project.
The designation of VIF on contract documents can be an extremely dangerous issue for contractors and construction managers. The impact of these dimensions, on the accuracy of the project schedule as well as the budget, must be determined by the contractor or construction manager at the time of bidding or budget consideration. Unfortunately, it is extremely difficult for the contractor or the construction manager, to clearly understand the impact that the need to VIF dimensions will have, on either their schedule or their budget.
It is extremely easy for the design team to simply shift these dimensional responsibilities onto the construction side of the project, without understanding the impact that this requirement will have on the construction schedule as well as the budget.
Contractor’s, it is vitally important that all the effects on your construction project be carefully considered, due to any VIF designations that the design team has placed on the contract documents.
It is a very easy and popular method of liability transfer, by the design team, and the contractor or construction manager must understand and professionally manager this liability shift.