现有实验室的管理人员在不久的将来将面临严重的问题。超过1000000个现有的实验室通风柜及其配套的补充空气系统可能需要进行改装，以符合即将出台的职业安全与健康管理局（OSI-IA）法规和各州的“知情权”法律。即使有很多人在场。日间抽油烟机在最大窗扇位置保持足够的捕获速度，在较低窗扇位置很可能有过大的表面速度。现有的旁路和辅助空气式通风罩不能充分补偿不同的窗扇位置，经理必须坚持改进，以保护其雇主免受未来的诉讼。面对这种情况，设施工程师能做些什么来确保实验室的安全，更不用说提高能源效率了？新建设施可采用最先进的系统和控制装置，包括等速通风罩、房间增压控制装置，以及位置合适的排气口和进气口。 不幸的是，现有设施在很大程度上不会有这种奢侈。许多工程师都预见到了这个问题，并检查了可用的系统。硬件和系统供应商已经在销售产品，而其他供应商正在开发。价格差异很大，关于性能和能源效率的说法也是如此。在本文中，作者回顾了一些组织是如何解决这个问题的。文中给出了应用、测试和记录的控制方法示例，以及协助设施经理的可用工具和程序。设施工程师可能遇到的各种类型的现有通风罩和供应系统将作为一些经验证的实用解决方案进行说明。案例记录、测试数据以及所有者的经验和评论是本文的一部分。要避免的一些陷阱，如污染物回收和室内空气侵入，包括: 研讨会，ASHRAE Trans。，第95卷，p。2

Managers of existing laboratories will face serious problems in the near future. More than 1,000,000 existing laboratory fume hoods along with their companion makeup air systems may have to be retrofitted to comply with pending Occupational Safety and Health Administration (OSI-IA) regulations and various state "Right to Know" laws. Even if many present.day hoods maintain adequate capture velocity at the maximum sash position, they most likely have excessive face velocity at lower sash positions. Existing bypass and auxiliary air type hoods do not adequately compensate for varying sash positions and the manager will have to insist on improvement in orderto protect his employer from future litigation.Faced with this situation, what can the facilities engineer do to make his laboratory safe, not to mention more energy efficient? Newly constructed facilities can incorporate state-of-the-art systems and controls including constant face velocity hoods, room pressurization control, and properly located exhausts and intakes. Unfortunately, existing facilities, for the most part, will not have this luxury.Many engineers are anticipating this problem and looking over the systems available. Hardware and systems vendors already are selling products, while others are being developed. Prices vary considerably, as do claims for performance and energy efficiency. In this paper, the author re/ates how some organizations have tackled the problem. Examples of control methods applied, tested, and documented are presented, as well as available tools and procedures to assist the facilities manager. The various types of existing hoods and supply systems the facilities engineer may encounter will be illustrated, as we//as some proven practical solutions. Case histories, test data, and owners’ experiences and comments are part of this paper. Some of the pitfalls to avoid, such as recycling of contaminants and room air incursion, are shown