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Implementation of the performance-based quality management

The SPF contractor fabricates the SPF product on site in accordance with manufacturer’s instructions. Nevertheless, the contractor may select one of many different foam systems, each exhibiting different thermal, mechanical, and fire performance characteristics. Therefore, the SPF contractor in addition to being trained in the art of polyurethane foaming must understand different aspects of the construction process.

The outcome of the contractor’s work will be affected by several installation parameters such as thickness of the foam, number of passes, and air and substrate temperature[1]. While the conditions of installation have a pronounced effect on all properties of the installed SPF layer, its performance is also affected by the design of the system itself. In short, performance of the building envelope component with SPF depends on understanding materials and their interaction with the environment by all people involved in the design, selection, fabrication, and maintenance of SPF systems.

Furthermore, the simple act of SPF fabricating at a location, is an effect of a complex process that involves five different industrial groups, each more or less willingly contributing to the final performance of field fabricated SPF insulation:

1)  manufacturers of raw materials such as polyisocyanate (component A), polyol, blowing agent, catalyst, surfactant, flame retardant and other additives (antioxidants, fillers) that are used to modify properties of the foam (component B)[2]

2)  system developers, who blend and formulate polyol mixture for a specific application[3]

3)  manufacturers of spray equipment[4]

4)  manufacturers of coating and protective finish systems

5)  polyurethane foam contractors, who purchase a SPF system manufactured by (2) and use equipment of (3) to fabricate the foam with a protective covering manufactured by (4)

One may use a spray, pour or froth polyurethane system (depending on whether the reaction starts before or after the foam application). Even within the spray systems, the reaction starts in such a broad range as 2 to 16 seconds. The fast foams are used in wall applications, and the slower are used for roof applications. HD-type and SHD-type SPF with densities above 45 kg/m3 (2.8 lb/ft3) are used in roofs. MD-type and LD-type SPF with a density below 37 kg/m3 ( 2.3 lb/ft3) are used in wall applications. Closed-cell foams with very low densities have been successfully used for air sealing applications.

Historically, improvement of materials and application systems had taken place over a long period in the form of small incremental changes. Introduction of new blowing agents, stabilized bromine compounds as fire retardants, wider ranges of application temperatures, new polymeric systems, fast-drying coatings, and improved application machinery (foaming robots) may illustrate the progress in this field. The outlook for SPF appears very good. Tye (1987) concluded that SPF has desirable characteristics such as:

"the production of monolithic joint free layers, potentially simple installation, consideration as both air and/or moisture retarders for appropriate applications, and the ability to choose from a range of formulations which provide suitable physical, mechanical and thermal properties for a particular part of the envelope." Significant growth potential is foreseen "where reduction of the effects of thermal bridges and air movement can be achieved."

The same assessment stated: " Adequate information on long-term performance and specifically on some relevant parameters which affect final thermal performance of materials, coverings and their combination does not exist. This includes coefficients of expansion, dimensional stability, water absorption, air and moisture (vapor) permeance, adhesion and cohesion especially at different temperatures."

This monograph, primarily based on knowledge developed during seven years of the joint SPI/NRC projects, answered many of the questions asked by Tye (1987). Methodology to predict long-term thermal performance of SPF has been developed and verified. Long-term thermal and mechanical performance of SPF manufactured with different blowing agents was carefully evaluated. Study of thermally driven moisture (movement caused by thermal gradients) created basic understanding of moisture transport and storage (absorption) in SPF. These laboratory investigations were designed to explain many of the findings from long-term outdoor exposures, such as studies of SPF roofing systems performed by Alumbaugh or Kashiwagi. The improved understanding provides the SPF industry with new opportunities and this industry is well positioned to meet the challenges of the coming decade.

While there are many new opportunities for the SPF industry, the extent to which these opportunities may be realized depends on the industry determination to maintain the leading system of quality assurance. The research reviewed in this monograph has shown that HCFC-blown sprayed polyurethane foam may have long-term mechanical and thermal performance as good or better than the CFC-11 blown foam. Whether consumers (specifiers) will accept that a new generation of SPF is better than the old one, depends primarily on Quality Assurance programs.

To promote and expand qualified use of SPF in North America, two organizations -- the Spray Polyurethane Division of the Society of the Plastics Industry Inc. and the Canadian Urethane Foam Contractors Association Inc. -- have established extensive quality assurance programs. These programs include the classroom training and field training that together with qualified experience, professional networking and updated material from different technical and industry promotion committees of the SPFD[5] constitute a strong basis for quality in the SPF industry.

The SPF industry wants to make sure that the SPF products provided to the consumer are of the highest quality, quality equal to or surpassing that of plant-manufactured materials. A field-fabricated product such as an SPF foam can offer technical benefits to the consumer. Industry-wide quality assurance takes away the “uncertainty” of field fabrication.

These programs may differ with local economic conditions and requirements of building officials, yet, they have the same technical basis over the whole North American continent. These programs include installer training and certification through rigorous accreditation courses and apprentice training and examinations for certified installers. The installer certification is a prerequisite for licensing the contractors on a yearly basis and providing them with an ID card.

In some areas, CUFCA has established a QA program, which provides an unannounced inspection system with spot surveillance (a record of each job site is forwarded to CUCFA to build a database tracking system).

The industry program includes a multi-level training curriculum combined with actual field experience to produce the required level of competence. There are four levels of training, with about one year of working experience ascribed to each of them, but any installer with a proven two-year practice is allowed to complete the course and take the examination. Typically, the program includes:

  1. introduction to foam systems, safety and transportation issues (apprentice level)
  1. equipment, introduction to foam applications, properties of SPF, troubleshooting
  1. product knowledge and advanced foam applications
  1. building science, client relations, managing the job, field testing

The SPFD accreditation programs are organized similarly, on basic and advanced levels, though they may differ in details. They are exemplified in Tables 37 and 38. Table 37 specifies information modules involved in training for different position within the contractor’s business. Table 38 gives a more detailed example, namely, the first course on fundamentals of SPF and coating systems.

Table 37. Contractor training as organized by the SPFD/SPI Inc.

Applicator
(level A) / Foreman
(level B) / Sales (level C) / Management (level D)
Fundamentals / Fundamentals / Fundamentals / Fundamentals
Roofing / Roofing / Project control / Roofing
Equipment / Project control / Professional selling / Project control
Materials / Equipment / Roofing / Professional selling
Roof inspection / Materials / Finance & accounting
Roof inspection / Managerial skills

Table 38. Course 101 on fundamentals of SPF and coating systems

Module / Content
1 / Introduction
2 / Industry standards and coating specs
3 / SPF chemistry
4 / SPF equipment
5 / Foam applications and workmanship
6 / Coating chemistry, properties, and safety
7 / Coating equipment
8 / Coating applications and workmanship
9 / Job site quality control
10 / Inspection, maintenance, and repair
11 / SPF self-defense / safety

Table 39 lists technical information available form SPFD/ SPI Inc.

Title or description of the information / Year, stock number
A guide for selection of elastomeric protective coatings over SPF / 1994, A 102
SPF systems for new and remedial roofing / 1994, A 104
SPF roofing buyer’s check list / 1989, A 105
SPF blisters, their causes, types, prevention and repair / 1989, A107
SPF aggregate systems for new and remedial roofing / 1990, A110
SPF systems for cold storage facilities (between -40 oF and 50 oF / 1990, A 111
SPF for building envelope insulation and air seal / 1994, A 112
Moisture vapor transmission / 1994, A 118
Glossary of terms common to SPF industry / 1994, A 119
SPF estimating reference guide / 1992, A 121
The renewal of SPF and coating roof systems / 1994, A 122
Thermal barriers for SPF foam industry / 1995, A 126
Maintenance manual for SPF roof systems / 1995, A 127

In Canada, the self-control of the SPF industry has also been supported by requirements of building codes and provincial regulations. For instance, the National Standard of Canada, ULC S-705 requires that the SPF contractor’s training must include the following:

·  description of chemical components, including their property and MSDS for each component (to be provided by the manufacturer)

·  safe handling and use of chemical components (also provided by the manufacturer)

·  operating parameters and maintenance of the equipment (equipment manufacturer)

·  physical properties of the SPF and limitations caused by the conditions of installation and use of the foam[6]

·  site and substrate preparation

·  chemical storage and handling, including disposal of waste material

·  limitations for use of SPF insulation

·  applicable codes and regulations

This monograph brings these two industrial accreditation and licensing programs even further by introducing concepts of the performance based quality assurance which combines technical specifications, performance assessment and on-site testing through the PBQA system. In this manner, the SPF industry can provide bidding documents that characterize long-term performance of SPF in construction systems and predicts energy use for many future years.

[1] Normally, SPF should not be applied at temperatures lower than 40oF (5oC), although specially designed foam can be applied even at 25oF (-5oC). Normally, SPF should not be applied when air relative humidity is above 70 % RH and wind exceeds 15 mph (7 m/s), unless wind screens are used. Furthermore, if the difference in substrate and air temperature exceeds 8oF (5oC) an adjustment in temperature of the proportioning unit (sometimes also the gun pressure) is needed.

[2] There are approximately sixteen major suppliers of chemicals and blowing agents

[3] There are fifteen to twenty system houses in North America

[4] There are four major manufacturers of equipment used by SPF contractors in North America.

[5] A close technical collaboration that exists between SPFD/SPI and CUFCA ensures the same technical standards are applicable over the whole North America.

[6] This information is to be developed by the system manufacturer.