Temporary packing measures, ranging from bracing, lashing, stuffing and wrapping to wooden or metal supports also can work incredibly effectively to reduce the risk of vibration damage. Removal of a minimal number of key components (such as glassware or high sensitivity instruments) also is a viable option if not carried to extremes. Air-ride trucks are readily available in almost any shape or size; these reduce the vibration on modules to realistically controllable limits.
Third, there's a nagging concern that what's fabricated offsite won't be what the organization wants or needs. This is a valid issue because many organizations, having decided to have something (large or small) constructed offsite, often basically abrogate all responsibility and rely on the fabricator's best judgment. When contracting anything offsite, the organization must convey all required information to the contractor. This includes a detailed design or design specification and also adequate information on in-house safety rules (both formal and informal) and equipment, operating and installation standards. Unfortunately, many installation practices and "standards" widely accepted at a given site are poorly if ever documented.
Some organizations seize on the effort necessary to provide such information as a reason for not considering modular construction. However, the savings possible almost always allow for this to be effectively addressed. And the effort leads to additional savings on the next project because it doesn't have to be repeated. Moreover, taking the time to collect and review these practices often generates additional savings from streamlined procedures, reducing unnecessary work or eliminating practices no longer required.
Guidelines For Effective Modular Construction
Carefully select the contractor. In addition to all the normal issues (technical skill, professionalism, quality, cost, etc.) the contractor must have adequate familiarity with the modular concept. Building a unit in a shop isn't hard but making sure it can be safely shipped and installed does require some significant training and experience.
Be willing to address problems that arise with an open mind. Spending some time and effort to reroute a line, widen a doorway, open a wall or accept a few days of scheduled downtime can go a long way toward reducing costs and improving the final product.
Learn from other's experience. Discuss problems and issues that have arisen with other users. Shamelessly question the contractor, the transportation company, the rigger and anyone else you can find about potential problems, past practices and horror and success stories and apply the results to your efforts.
Plan, plan and plan some more! No project ever suffered from too much advance planning. Modular projects, in particular, are very poor at trying to address issues in the field as opposed to upfront. Recognize that you may have to do a higher level of design, layout and review than you're normally accustomed to. You'll probably find, however, that this extra effort pays high rewards not just in the modular component but in the rest of the project as well.
An Under-Appreciated Option
Modular construction is a viable alternative for many pilot plants. Done properly it can reduce costs, alleviate onsite restrictions and produce a high-quality cost-effective unit.
Avoid Potential Problems
These 10 tips can help you forestall difficulties:
1. Select the contractor carefully. Make sure you have fully investigated its capabilities, experience and performance. Thoroughly check references.
2. Carefully plan the route the equipment will take into your facility. Look at alternative paths. Be open to relatively minor work such as rerouting lines, opening up doors or walls or temporarily relocating equipment that may allow larger modules to be brought in.
3. Recognize that larger units may come in several modules for easier shipment. Accept that some onsite erecting may save significant transportation costs and time.
4. Allocate adequate time for the extra planning and coordination modular construction requires.
5. Thoroughly review proposed piping and instrument drawings before committing to construction. Make sure fallback positions exist for new or novel approaches. Check that all process concerns are adequately addressed. Verify that interfaces with existing systems are fully dealt with.
6. Carefully evaluate the proposed skid layout for safety, ergonomic and process issues.
7. Ensure the design is fully and completely reviewed for safety. Confirm that detailed hazard analysis and risk assessment is conducted before the design is finalized. Check that the contractor understands all in-house safety rules, both formal and informal.
8. Make certain the design is comprehensively reviewed for process, operational and maintenance concerns and preferences. Use site-standard equipment suppliers and piping and wiring practices as much as possible.
9. Recognize the final product may look and seem different from units built in-house. If adequate reviews and planning have been conducted, this shouldn't be an issue but differences always make people feel uncomfortable. Make sure this is recognized and accepted in advance or the final product always will be suspect in some peoples' minds.
10. Obtain full and complete documentation from the contractor. At a minimum this should include electronic copies of all drawings and copies of all manuals, calculations and purchase orders..
Richard Palluzi is a senior engineering associate at ExxonMobil Research and Engineering Co., Annandale, N.J. E-mail him at firstname.lastname@example.org.